(Borrowing from my earlier answer here...)
re: actually performing the backup
Backing up a native Access database is simply a matter of copying the entire database file (.mdb for Access_2003 and earlier, .accdb for Access_2007 and later). Any scripting language would work, even a simple Windows batch file that does something like
copy /Y d:\apps\databases\mydatabase.accdb z:\backups\databases\*.*
re: automatic scheduling of the backup
The Task Scheduler in Windows could take care of that for you. Once you've created your script to copy the database file(s) you can create a scheduled task to run it periodically. See the MSDN article Using the Task Scheduler (Windows) for more information.