Is There A VCS (version Control System) For ASP ?

As the subject states, does anyone know of a VCS for ASP/VBS files ?

We are using the Liberum Help Desk system, which is "open sourced under the GPL license and free for use", and are about to make some changes to the system.

As each new version of Liberum is released, we may need to re-apply our changes to the new source code. Any easy ways of doing this, or any good VCS available ? Any tips to help cut down on the work involved to re-apply our changes, for instance, the use of includes would be obvious.

Our version of the (Access) db will be different from the Liberum releases, and I guess using stored queries would be in preference to 'hard coding' the SQLstrings ? I also hear stored queries are faster.

With each new version, we would need to find out (i) Differences in the new release to the previous release, and (ii) Diifferences between the new release and our 'version' of the product. Any easy methods to do this, rather than a multitude of "file compares" ??