You can't escape the government (or more specifically, "a government")... not while you're on Earth. The best and easiest way to do what you want is to identify the persons/companies in power and persuade them to give you that freedom, offering something useful for them in return.
It's really not that hard, and easier than establishing a new nation in the middle of nowhere, as attractive as that might sound...
It's funny you mention that - we studied Sealand as part of my Public International Law course about 5 years ago, and that's pretty much the conclusion that we all came to. The "best" things a country can do are only worthwhile with international recognition. Even Tuvalu (population c.10,000) gets its own TLD (.tv), which has been its prime source of income for some time.
Even more specifically, the US government. There are many governments on Earth you can escape from, but not the US. If they want you bad enough, they'll get you.
well, crud! I honestly did not mean to create a duplicate. I figured trying to submit this would lead to the inevitable earlier submission, but that didn't happen. I guess we used slightly different versions of the URL.
As it's been said before, if the government (especially the US government) wants you - they're going to get you. For the most part, even servers in third world nations (where it would be perfectly legal to host whatever you're hosting) would still buckle under the pressure of a US-3rd world standoff. Your best bet is proliferating your assets to multiple areas.
Actually The Pirate Bay had an interesting idea about this. They are planning on launching their servers high up into the atmosphere. An elegant solution imo.
http://news.ycombinator.com/item?id=3766543