Just installed firefox 1.5 beta 1 as there're RPMs for Suse 9.3 available.
Works so far, I just miss the Gnome theme and the searching for extensions updates didn't work completely. Looking on the homepages revealed much more working ones. As Firefox 1.5 is beta still, it's no problem to use beta versions of extensions as well. ;-)
The current SUSE 9.3 RPM doesn't want to close all open windows on pressing Ctrl-W any longer. That was the most annoying bug... ;-)