I used to get my daily Dilbert dose via the free Comic Basic e-mail subscription but it does not include the Sunday Dilbert comics :-(
The Unofficial Dilbert RSS feed, on the other hand, includes all the stripes so I don't have to remember to check the Sunday comics at regular intervals. You can subscribe with FeedBlitz to get the Dilbert comic via mail if you don't want to use a RSS reader. Please let me know if you find RSS feeds for Monty and Unfit.
Thanks for the tip Ale!