If you are using the version control integration features in Dynamics AX you may be using Visual SourceSafe as the version control provider. If you do, you are probably aware that Visual SourceSafe has been in maintenance mode for several years. You may even be looking for a replacement - after all your source code is a valuable asset, and it needs a reliable and sustainable home.
Team Foundation Server (TFS) is the natural replacement offered by Microsoft - and it is also supported by Dynamics AX 2009. However, TFS has so far been two complex and too costly to be a real alternative for smaller teams.
With TFS 2010 this is changing - for more information see these two blog posts: