Problem is, we have developed a small CMS, that is different per implementation (currently).

Of course development of this is never complete. Sometimes, we are working on more than one project that implements it (by copying-pasting the code files of the CMS to each project), and we add a new feature that we want to share on other projects as well (these can be small ones too, ie a custom ajax JSON controller - we use MVC)

What we want to do is quickly and uniformly share the code with all other projects, via a version control system (or something similar), and generally organize the workflow as we know this isn't a very good workflow that we have. What would you suggest?

Also, at the momment, the software we use is Visual Studio 2010, so we are strongly considering TFS, but even if we get it we still don't know the ideal workflow, or even if TFS supports what we want to do.

Edit: Also note, we have specific implementations that have modifications over the CMS base that we want to KEEP only in the project area. (ie: a specific feature that we DONT want to share with the base CMS code)