Although, I don't have experience with Gitlab, I did create a screencast about git/gitolite, which can do 90% of what you want @ http://sysadmincasts.com/episodes/11-internal-git-server-wit...

Then look at something like Gitweb [1], cgit [2], or Gerrit [3] to front the repo. I personally use git, gitolite, and gitweb.

[1] https://git.wiki.kernel.org/index.php/Gitweb

[2] http://git.zx2c4.com/cgit/

[3] http://code.google.com/p/gerrit/