The debs are already available for Debian unstable. I grabbed it and Mozilla 1.1 at the same time. Mozilla keeps getting better -- I noticed the tabs seem a lot smoother and faster now, but it is still behind Galeon in features, speed, and especially ease of use. I really can't praise Galeon enough, it is truly the best browser I've ever used.
RPM dependencies for could be tricky, that is the main reason why I switched to Debian. You have RH 7.3 right? This is probably the right RPM for your system, if it is wrong it will give an error: [rpmfind.net...]
With Mozilla, your package manager is looking for the latest RPM version of Mozilla, you will have to use the Mozilla rpms from mozilla.org. They could be found here: [ftp.mozilla.org...]
You will need: mozilla-1.1-0.i386.rpm mozilla-psm-1.1-0.i386.rpm (SSL) (might be one more that it will ask for)
I am not sure if your system is dependent on an older version of gdk-pixbuf or not. When you try to install it use -Uhv. The 'U' will tell rpm that you want to upgrade package, so it will replace the old one if possible without breaking dependencies.
If you end up in dependency hell, try installing the older version of Galeon from your RH CDs. It has been quite good for a while. Or, you could try installing from source.