It depends on the state. In California non-competes are unenforceable except in very narrow situations, like if you sell goodwill to a company or you are part of a partnership that has gone through a dissolution. Certainly, this guy's non-compete is unenforceable in California.
It'd be really nice if some hacker would put together a comprehensive map/list of non-compete status per state (or if they have) since there are a few states outside of California too. Wikipedia seems to do OK in this regard, but it seems like there should be a lot more info out there.
