if you have a scheduler (i.e. nt scheduler) you could kick off a batch file each night that opens the mdb (from your machine or the server) and executes an autoexec program (built by you) that emails the report to the user (or drops it to a location on the network) and then exits out of the database.
or
if you have the Developer Edition of Access you can run a setup program on the users machine to only give them the "run-time" version. then, build/provide the user a GUI (front-end to the back-end tables) that will give them the ability to generate the report via command button, etc.
or
try Crystal Reports.