Foxmarks is a Firefox extension that allows you to keep your Firefox bookmarks in sync.  It works by keeping a copy of your bookmarks out on the Foxcloud server at http://www.foxcloud.com.  Every minute it checks for any changes and then synchronizes your local copy to the copy on the server.  This is very handy if, like me, you use firefox on multiple machines (I have 4 I use frequently) and have a large number of bookmarks.  Because you information is stored on the Foxcloud server you can access your bookmarks from any place you have internet access.

Just one more reason to love Firefox.

Download the extension here: https://addons.mozilla.org/firefox/2410/

Homepage:  http://www.foxcloud.com/wiki/Main_Page

Personal Bookmarks page:  http://my.foxcloud.com/