Gitblit is an open-source, pure Java stack for managing, viewing,
and serving Git repositories. It's designed primarily as a tool for
small workgroups who want to host centralized repositories.

Gitblit WAR is what you should download if you already have a servlet
container available that you wish to use. Jetty 6/7/8 and Tomcat 7
are known to work. Generally, any Servlet 2.5 or Servlet 3.0
container should work.

Gitblit can be used as a dumb repository viewer with no administrative
controls or user accounts. Gitblit can be used as a complete Git
stack for cloning, pushing, and repository access control. Gitblit
can be used without any other Git tooling (including actual Git)
or it can cooperate with your established tools.

WWW: http://gitblit.com/