Yes, Crawler Toolbar works not only with Internet Explorer® 5.5 and higher, but also with Mozilla® Firefox® 2.0 and higher, however the functionality is currently limited.
At this time Crawler Toolbar allows you to fully enjoy functionality of Web Security Guard with Mozilla® Firefox®.
If you want to use Desktop Email Notifier, you can enjoy its System Tray notification, even if you are not using Internet Explorer®.
However, we plan to introduce more Crawler Toolbar features for Mozilla® Firefox® 2.0 soon.