There are lots of mobile friendly careers.. and IT is generally one of them (anything you can do remotely, or even finding traveling service/training jobs).
Personally, I continue to run the same software development biz I ran when I was more stationary. Plus Chris and I take on cool tech consulting gigs from time to time, and have even tried workamping packing boxes at Amazon.com during peak season (well, we did that more for the fun of it, the $$ was a nice bonus that funded a few months of travel). We've also gotten into developing iPhone apps that create some nice residual income.
Other mobile careers that we've encountered include various medical professionals, photography, writing, graphic design, balloon animal twisting, tattoo artist, accounting, performance art (music, dancing, hooping, story telling, etc), dance instructor, personal/business coaching, jewelry making, sales, and so many more.
NuNomad recently made a great posting showing 25 mobile careers with examples of people doing them:
http://www.nunomad.com/blog/25-career-ideas-to-design-your-location-independent-lifestyle/
Basically.. if you have skills and confidence you can get work when you need it, you'll do fine. Embrace agility, design your life to be the least dependent on cash as possible - and you'll thrive.
I also need to get back into the swing of things and get down to editing the footage I took at the recent gathering that profiles many of the NuRVers households that answer these sorts of questions.
- Cherie