Change of plans: I don't think I'll do the CSSTint-rewrite this time.. I've got a much more interesting idea. While it's still too early to talk about this, it involves Qt 4.4 (yay!) and OpenGL. I will write more about it when (or if) I have something to show.
Right now I'm wondering whether to go with SourceForge like I always have, or to use Google Code. Google Code seems nice and simple, as I'll only need SVN and some pages (or a wiki). And yes, it'll be open source.