Git has a hand full of GUIs available on Mac OS X, gitk proved a little tricky to use but GitX has some nice features.

Normally I would recommend just working from the command line but GitX has the ability to stage ‘svn speak for prepare for a commit’ individual lines or blocks of lines. So if you forgot to commit between 2 bug fixes you can stage and push blocks of code instead of the whole file. It does not seen to be able to add new files to a repo yet though or maybe I just need to spend some more time with it.