So I just read the Knowledge Base article about iCal and the Address Book and wondered if one could do the same type of thing in different programs. Sure enough you can! I went to the Mail application in 10.2 and set a new rule for my incoming mail. The rule should read like this:
If ANY of the following conditions are met: EVERY MESSAGE CONTAINS [your email address], perform the following actions: FORWARD MESSAGE to [your mobile email address] and hit OK. Now whenever you recieve an email in your inbox, you will get the message on your phone. You can tweak the EVERY MESSAGE to be anything you want so you can be more specific if you would like.
Mac OS X Hints
http://hints.macworld.com/article.php?story=20020927052237683