i don’t use cvs nearly as much as i should, which is a shame, since it comes with mac os x’s development tools:

“CVS supports all sorts of additional operations that are useful to large teams. However, for our purposes (which are much less demanding than software development), we can take the functionality that we’ve just described and use it to solve the problem of managing our own data on multiple machines. Even if you are the only person to use your data, CVS can help you easily maintain it on as many machines as your bank account can fund.”