To pull from git do the following
for yum:
git clone http://linux.duke.edu/yum/git/yum.git
for yum-utils:
git clone http://linux.duke.edu/yum/git/yum-utils.git
for yum-metadata-parser:
git clone http://linux.duke.edu/yum/git/yum-metadata-parser.git
for yum-updatesd:
git clone http://linux.duke.edu/yum/git/yum-updatesd.git
To update once you've gotten it.
git pull
Git Web is available from: http://devel.linux.duke.edu/gitweb/
If you're a committer your access is using ssh. You can access the git trees via:
git clone ssh://login.linux.duke.edu/home/groups/yum/git/$module_name.git
If you have additional questions contact the devel list.