I have been using the Foxmarks add-on for Firefox to synchronizes my bookmarks between different computers.
Just got to know that Box.net has made a similar tool that backs up and synchronizes your bookmarks called Bookmarks Synchronizer 1.0.2.
It's very simple, you can set it to auto update you bookmarks so they are synchronized wherever you go, or you can manually backup and restore bookmarks. The bookmarks are then stored on Box.net and can be accessed anywhere.
Thanks for the info Brian.