It's possible to do things either way. If your developers have a standard corporate desktop, so that paths and
IDE settings are likely to be just the same for everyone, then you can check the IDE project files into CVS along with the project. On the other hand, many teams have developers with some variation in their environments, so identical project files would not work for all team members. In this situation,
you should not check the project files in; just check in the source code,
Ant files, etc, and not the IDE project file(s).