Although KDE is currently using SVN, we're working on moving to git. Also, a growing number of developers are using git-svn to contribute to KDE.
There are many resources available for learning about Git; the techbase pages below provide a kde-specific introduction, based on the most common tasks. After those links is a list of external documentation we've found useful.
Note: these pages are not complete. help would be appreciated. :) The idea is to provide information in more of a 'recipe' style than 'tutorial': first provide simple commands that people can use Right Now for straightforward tasks, then links to other pages or external git documentation for the tricky things.
Amarok has their own git tutorial, which has a fair amount of overlap with these git pages (we're copying from them ;)
If you want to learn more about git, see the following resources: