GitX: Git GUI for OS X
gitx.frim.nl
gitx.frim.nl
Best of all: it's open source and makes great use of HTML & JavaScript. Even if you don't know ObjC, you can contribute.
edit: Gorgeous logo too!
Problems:
There is no support user based auth, so you have to set up SSH keys. Pain for our non-techies in the group. You should be able to add users and get access via user/pw/repo url.
Bigger problem is the lack of Windows support. We have 2 people (the non-techies) on Windows and expecting them to learn the command line stuff isn't realistic.
I've asked to be reminded but I've heard nothing so far.
The fact that Git clients store full histories is one of the things that makes it less like a filesystem; it is, instead, a system for managing overlapping patch streams.
Check out the core svn C APIs (nb: our product is built on them); it's basically an open/close/read/write/readdir system with one additional "history" option (which history snapshots an entire filesystem, not just individual files (like CVS) or patches (like git).