Khardashev Scale

A good standard of measurement of measurement for long term progress is the Khardashev scale, an excellent discussion of which can be found:
http://en.wikipedia.org/wiki/Kardashev_scale

Of course the rapid accelleration of technology may mean that we will be substantially different as we move off planet. An excellent discussion can be found in Ray Kurzweil's new book, The Singularity Is Near.
http://www.kurzweilai.net/index.html?flash=1

If we truly were able to "Upload" to a digital substrate, we could afford to take our time to get to other places--or perhaps, with an ability to think so much faster than our current brains, we would cease to be interested in things that interest us now (as such experiments and activities might appear to move at glacial speeds). We might choose instead to forego exploration and expansion and rather create our own content for exploration, expanding only in computational ability, making use of available solar energy and solar system materials. http://en.wikipedia.org/wiki/Dyson_sphere

While many seem already quite convinced that there not only is likely to be extraterrestial intelligent life, but that it is already here visiting us ( http://www.exopolitics.org/ ), I am personally less than convinced E.T. has visited us. Kurzweil also makes an interesting argument that we may in fact be alone in the universe.

There is also an interesting discussion on the subject here:
http://www.futurehi.net/archives/000106.html
http://www.futurehi.net/archives/000607.html

If we are alone, than that certainly carries with it a moral imperative to spread. If it is not the case, then we certainly need to be prepared for an eventual meeting.

Our own experience on Earth shows that rarely do technologically underdeveloped societies fare well when they meet technologically superior societies. Jared Diamond's Guns Germs and Steel is an excellent discussion of why some societies move faster than others. http://en.wikipedia.org/wiki/Guns,_Germs_and_Steel

I personally doubt that the laws of evolution work differently elsewhere, so I would expect the following:
1) They will be self-interested
2) They will be expansionist
3) They will seek the most payback for the least payout
4) They will not look kindly on competition

When we look at who survived well and why, we can see that there are limited examples of independence, which offer possible strategies should such an encounter ever occur:

1) Japan survived because it quickly adopted technology, and opened enough to trade that it was less trouble for the foreign powers to trade than to occupy. A terrific book on how this was accomplished is: Romulus Hillsborough's Ryoma, Life of a Renaissance Samurai http://www.amazon.com/gp/product/0966740173/104-2260096-0408727?v=glance&n=283155
2) Thailand survived because it played off competing powers

3) Small trade ports survived because they provided a laise-faire trade environment

4) The United States gained its independence because its enemy had long logistical lines which sapped its wealth and it had another enemy.

In any case, it would pay to be the E.T. visiting them first, rather than the other way around. [One fun way to at least keep our eyes out is to donate your spare screen-saver time to the largest parallel supercomputer project in the world: http://setiathome.berkeley.edu/ ]

China is a great example of what happens when you turn from expansion and exploration, check out: Gavin Menzies' 1421 The Year China Discovered America. http://www.1421.tv/
http://www.amazon.com/gp/product/006054094X/qid=1143305617/sr=2-1/ref=pd_bbs_b_2_1/104-2260096-0408727?s=books&v=glance&n=283155

And a fantastic example is Fancisco Pizzaro's defeat and capture of Inca king Atahualpa by a tiny fraction of mounted, steel-equipped conquistadors against a huge Incan army armed with neither.

Just think if an advisor had come to Atahualpa and said, "Say, we should be investing in boat techology. It is possible that beyond that vast ocean there are valuable lands, and that on those lands may be other intelligent people. It is possible they could make it here, and if they did, they probably would have learned some militarily useful things along th way."

Only to be refuted, "No way, there is no evidence that there is anything useful out there, or that there are any people! Such shipcraft is just fantasy--we can barely get a few miles off coast. Furthermore, any men advanced enough to make it here is a ship would be so technologically superior that and so much more intelligent, they would be gods we would want to worship and serve anyway, or they would have evolved to a higher level of consciousness and not be interested in petty things like gold or land or power."

Better to do unto others says the realist.

The Long Road Ahead

Absent constraints, the natural urge of all life is to grow and expand into new ecological niches.

Space Exploration is primarily useful only as a precursor the expansion of humanity (and its children), and those portions of the biosphere we wish to take with us. The guys who have it right are those who look at space as a frontier, and seek to open it to the full powers of human creativity and market forces:
http://www.space-frontier.org/

Some of the more exciting near-term visions I have seen are:
http://www.spaceislandgroup.com/home.html
http://gaiaselene.com/
http://www.jamestownonthemoon.org/

Of course, most of the places we want to visit are very long way off. Ultimately, we will want other means of propulsion than just chemical rockets. For a short time, Marc Millis at NASA ran a terrific program at NASA to turn over possible stones looking at this. Sadly, NASA terminated this program, and no-one, not the USAF, the DOE has picked up the slack.
http://www.grc.nasa.gov/WWW/bpp/
Marc is now continuing to bring attention to this through a new organization.
http://www.centauri-dreams.org/

In the popular media, one place to look for buzz in this area is:
http://www.americanantigravity.com/

Two wonderful repositories of some of the wonderful designs of the past, when we were a much more ambitious people are:
http://www.astronautix.com/
http://www.abo.fi/~mlindroo/Space.htm
Another terrific resource is Ron Miller's Book: The Dream Machines
http://www.amazon.com/gp/product/0894640399/104-2260096-0408727?v=glance&n=283155

Of course, expansion is going to take a while, and if managed correctly, the Earth should last us until our Sun changes radically, several billion years from now. That creates near term priorities:

1) Protect the Biosphere from catastrophic threats (Comets and Asteroids)
The Earth has been hit before, and it will be hit again.
http://csat.au.af.mil/2025/volume3/vol3ch16.pdf
http://csat.au.af.mil/2020/papers/app-r.pdf
http://neo.jpl.nasa.gov/
http://impact.arc.nasa.gov/
http://www.b612foundation.org/

2) Solve the Energy Problem (With Space Resources)
http://www.spaceislandgroup.com/solarsat.html
http://www.lunarcommerceroundtable.com/lcr2_presentations.html
http://www.space-frontier.org/Projects/spacesolarpower/

3) Manage the Climate
Even assuming we can mitigate or solve the greenhouse gas problem, we can expect there to be unwanted changes in our climate, and varriatios in the solar constant. It would be wise to start developing the models and the tools to ensure we can assist the Earth in maintaining homeostasis.
http://www.llnl.gov/global-warm/
http://www.thespacereview.com/article/490/1