There is a sticky thread for listing hosts that provide free WebDAV space:
http://forums.omnigroup.com/showthread.php?t=11054
P.S. Be aware that it is very unlikely that these free hosts use any form of encryption for your data while synching, so if you have sensitive work data in your database, I wouldn't use them and would just plunk down the money for one that does (e.g. MobileMe).