FaveCave

Store your IE links online; easily sync with all of your computers.

New Users: Just type a unique username & password, then click Save to Cave.  DO NOT reuse a password you use elsewhere.
Returning Users: Retype your username & password, then click Load or View Cave.

NEW: The otherwise excellent Windows XP SP2 disables the API call this service requires.  No known workaround.  Sorry folks.  I've heard good things about the free FavoriteSync, but I haven't tried it myself, so I can make no guarantees.  You can still View your previously saved bookmarks, and might even be able to File|Save them to disk and use File|Import to import them.