There are thousands of "royalty free" fonts out there with very relaxed copyright claims to them...
The one dangerous thing there, though, is that I've seen a *ton* of 'free' or 'public domain' fonts on various websites that I know for a fact are indeed copyrighted by someone else... Personally I like the aenigmafonts.com site, where there are a ton of fonts done by a single person who expressely made them royalty free, and even allows them to be used for commercial purposes.