I've released version 0.1 of OPML Link Publisher, a Java application that publishes an OPML link directory outline as a bookmarks.html file, which can be automatically loaded by Mozilla or Netscape Navigator and manually imported into Internet Explorer.
I wrote the application because a Mozilla crash wiped out my bookmarks and I was tired of having bookmarks in several different browsers and other files. Radio UserLand's outliner can be used to create link directories (other outliners may support the feature as well), and since I already had several hundred bookmarks in that format, I decided to use it as the source material for all bookmarks.
I plan to add additional output formats such as Internet Explorer favorites and Dmoz-style Web directory pages.
The project, which is released under the open-source GNU General Public License, was a good test of the XOM XML Object Model Java library, which made it easy to parse OPML files.