Multiple Environments

[eluser]CroNiX[/eluser]
Git itself is command line and there are GUIs available for all platforms. A lot of free ones and some commercial. I use Zend Studio for an IDE myself, and while it does have git support I still prefer the command line or other gui tool. Git has GitGUI built in which is more than sufficient for most GIT operations, although learning the CLI is really best.

There is a plethora of tutorials on the web on how to set it up on your mac.

Whenever you switch branches in git, all of your code in coda should update to that version of the code automatically. Not sure how coda works, but you might be able to just refresh the project or something if it doesn't. Whenever I switch branches and use Zend Studio, when I try to open a file that has changed it asks if I want to reload the file to the current version. So I'm assuming Coda is similar in that it knows when the file was changed outside of coda.