source control suggestions?

I just went through the PADNUG message board archives and I was 
surprised that there was little about source control in there. What 
would you suggest that is free/cheap? I'm hoping to find something that 
is easy to use, has a nice interface and will allow me to keep a source 
on my home system and expose the database to an external user (for 
collaboration). That's a good place to start. Suggestions? Before we get 
started with this, I have SourceSafe and I'm sort of happy with it. I've 
seen better in the *Nix world and that makes me sad :(..

-- Justin