Developing an Android based device is not a simple task, and usually need a team to work together. Some members handles kernel drivers and BSP, some for HAL and middle ware, and others for framework and applications. There're some tools to simplify those daily complex jobs, e.g. Apache Marven for project management and Hudson for continues integration. There's a good article to introduce such environment by Kamil: http://novoda.com/2010/08/13/android-continuous-integration-android-maven-plugin/
For a small team, it may too overloaded or you may not want to learn so many tools. So in this article, I'll try to construct a simple and easy to use environment for starters.
1. Install git-daemon
git-daemon is a really simple server for git repositories. It listens to TCP port "DEFAULT_GIT_PORT" aka 9418.
$ grep 9418 /etc/services
git 9418/tcp # Git Version Control System