oggsync google calendar sync
mail2web (free exchange)
emoze (also free exchange)
You can also check this thread out for more info
http://forum.ppcgeeks.com/showthread.php?t=41177
If you're a student you can check whether your university has an agreement with Microsoft for an exchangelabs account
Here's a tutorial that explains how to do it with mail2web and 2 phones
http://www.asktheadmin.com/2008/02/s...ne-device.html
+1 Dashwire, i haven't used it before but heard it was good