I lived a PT lifestyle when I was younger. I lived in Singapore, Japan, Australia, Switzerland, and Germany, going back to Japan repeatedly. Doing this though made life difficult for me at first. The American "system" doesn't reward this type of lifestyle, but there are ways around this if you know the ropes.

Selling Internet products such as e-books is a good source of income. I actually never had a problem finding under the table jobs in foreign countries. It is very easy in asian countries. In Japan I was paid around $50/hour to speak english to students learning english. You can find a cheap room to stay at somewhere and join an inexpensive gym where you can work-out and take a shower.

Different countries offer different advantages. Some are definitely more friendlier than others.

Being PT gives you more freedom than almost any other lifestyle because as a tourist you're constantly under the radar. Tourists are usually given favourable treatment and considered harmless because of they're temporary nature. Governments almost never snoop, spy or arrest tourists unless they arise suspicion for some reason.

Another advantage of being PT is that you don't pay any taxes, unless of course you're American because you're required to pay taxes to your government no matter where in the world you reside unless you renounce your American citizenship (how scandulous & f*cked up is that!??).

Anyway, I'm seriously considering entering the PT lifestyle next year, although a lot will depend on what happens in the world and whether my internet business starts to make the kind of money I'll need.

Obviously the PT lifestyle isn't for everyone. If you have a family or you have a lot of ties to where you live, or you just get homesick real easily then it's probably not a lifestyle that all will find appealing.

Another requirement of being PT is that you need a reliable source of income because as a tourist you won't be able to get jobs in the countries you're living in.

Most PTers these days have internet businesses that allow them to work from anywhere providing they have access to the Internet.

Anyway there's a few good resources on living the PT lifestyle. My favourites are:

Sovereign Life
http://www.sovereignlife.com/
This site is run by David Macgregor, I recommend signing up to his newsletter which is free, he also has a paid membership site that is full of information and resources on how to go PT as well as setting up offshore bank accounts and businesses.

PT Club
http://ptclub.com/
This is another great resource on the PT lifestyle as well as many other services that help you increase your freedom and privacy. See http://ptclub.com/whatispt.html for a better explanation of PT.

Here's a bit about the subject on Wikipedia
http://en.wikipedia.org/wiki/PT_Perpetual_Traveler