Consulting’s always a good place to start if you can scrape the client list together. I’m in IT and do a fair amount of side business this way. I’ve been growing clients for a few years with an eye towards doing it full time. The jump is hard to calculate, of course…it’s always a leap of faith in your abilities.
Any kind of knowledge-based service business will weather a recession better than a retail or manufacturing business, I think. Sounds contrary, I know, but in a recession we’re all trying to cut corners and piece-work consultants can cost less than keep staff on-line AND you can control your costs to a finer degree with not-to-exceed work contracts or the simple expedient of pulling the plug on a consultant.