One of the first things you need to understand about Firefox themes is how to package them. It’s really simple, so be prepared to have an easy first step.

Firefox themes are just zip files, renamed to jar. So, if you can create a zip file, and rename a file, you’ll be done in no time. You may have to make a few tweaks to how XP/Vista shows files though.

Update: The file structure is now different with Firefox 3.6. See the updated file structure here.