How is the user going to make an informed decision. If you have a hand made XML this implies that you will store some information on the intranet-update-server for every new code bit. This is a lot of maintenance.
That's why I mentioned that cvs dates. All entries to the CVS logs between the dates should be available as a comment the user can see before he decides whether he wants to upgrade. This is considerably less maintenance than releasing packages and storing release notes with them. Furthermore it gives you the flexibility of not having to release so often :).
