Other options:

For an unofficial Firefox 10 compatible version (TenFourFox) that runs on PowerPC Macs with OS X 10.4.11 or OS X 10.5.8 you can look at:

• http://www.floodgap.com/software/tenfourfox/
• http://www.macupdate.com/app/mac/37761/tenfourfox

• http://code.google.com/p/tenfourfox/wiki/ReleaseNotes100
• http://code.google.com/p/tenfourfox/wiki/PluginsNoLongerSupported
• http://code.google.com/p/tenfourfox/wiki/AAATheFAQ

I have noticed that it is, in fact, hard to find a place to ask a question of Mozilla directly. As far as TenFourFox is concerned, I'm not sure it is the ideal solution. See:

http://forums.mozillazine.org/viewtopic.php?f=23&t=2323835

and

http://support.mozilla.org/en-US/questions/917112

Not to harp on the situation, but us PPC users really will be in a bad spot once Mozilla stops supporting 3.6.

Unfortunately, TenFourFox is probably your only way of getting anything newer than Firefox 3.6.x on a PPC. Unless there is another unofficial version out there that I am un-aware of.

I did forget about Camino, which while it is built on the Firefox 3.6 platform, it may suit your needs better. Camino Browser