If you prefer Mozilla’s Firefox 3 brower to Internet Explorer, you are probably familiar with some of the many add-ins and extensions offered for the program. Mozilla recently finished up its Extend Firefox 3 contest and annouced the winning programs.

Three add-ins were awarded the grand prize. The first winner was Pencil, a tool for GUI prototyping and diagramming. The program is not likely to be very useful for most users, but it is a great tool for anyone needing to create a GUI prototype in short order.

The second winner was an addon called Tagmarks. The program adds a set of icons to your toolbar that makes it easy to create tags in your bookmarks. Tagmarks also allows you to save pages to your delicious bookmarks, as well as your  local ones.

The final grand prize winner was HandyTag. This little tool will automatically suggest tags for your bookmarks based on tags suggested by delicious users and through the use of its internal keyword extractor.

Given the popularity of the many web 2.0 sites, the fact that two of the three winners are tagging utilities is not a big suprise. There are many other useful addon programs for FireFox, so be sure to explore and have fun.