One is <A href="http://bookmarkbridge.sourceforge.net/">Bookmark Bridge</A>, a simple utility that synchronizes bookmarks across multiple browsers like Internet Explorer and Firefox (caveat: this is a beta program and occasionally hiccups). The other is <A href="http://extensionroom.mozdev.org/more-info/bookmarkchecker">Bookmark LinkChecker</A>, a Firefox extension that identifies and helps manage the deadwood.