One thing to consider if you are up to the bleeding edge is Linus's "git" source code manageemnt system used to maintian the kernel. Haven't tried it my self as it is bleeding edge. Another source code management system is "subverson". Any of these approaches requires a bit of thought in how and where the repositories will be kept. I'm not totally up on it but SourceFroge might be an answer too, I'm not sure of its licensing status though.
The nice thing about SourceForge beyond the interface to the web is that it allows grouping of many components of a project together. Things like a home page, issue tracking, release code, development code and a forum space. Issue tracking can be very useful. Last I knew Sourceforge still used CVS so tools associated with that work too. Of the software mentioned so far Sourcforge seems to be the only package that offers collaboration of more than just the software developers. The big problemm is that I don't know if Sourceforge is licensed GPL or any other way. There may be some wisdon in getting a support contract anyways, it does take a bit of effrot to keep a server up and running and you are not likely to want to employee somebody doing that. Another nice thing aobut Sourceforge is that there are example sights out there you can visit to get a feel for how it would all work.
Git is also very interesting and has seen a huge amount of devlopment take place recently. That would be bleeding edge though.
Note also that many of the Source code management programs have trouble with binary data. Something to keep in mind if you have data in that form. So a program that relies strictly on CVS for all data may be an issue.
Just a note there is a difference between being web based and network enabled. Almost all revison control systems have some sort of netwrking cpaability. Web based usage usually involves a differrent software package. This package gives one an interface to the repository via a web browser.
I'm not an expert here so take the above with a grain of salt. For a large distributed company a bit of thought has to go into all of of this. One thing to look out for is easy access for non technical (programmers) users.
Dave |