Update 2008-08-27 : Version 1.1, compatible with Firefox 3, has been released.
In short, it is coming, but I don’t have an exact timeline. I predict about 2 weeks.
We (at Briks) have been up to our gills in other work and this never made it to the top of the queue. It has been FF3 compatible a while now for the most part, but we got stuck on an XPCOM registration issue that broke some services, including Flickr, and have not had a chance to revisit.
Sincere apologies to Fotofox users and in the meantime I recommed using one of the tools recommended from the photo service that you use.