Hello,
TenFourFox is the most up to date browser for our PPCs, they even have G4 & G5 optimized versions...
http://www.floodgap.com/software/tenfourfox/
I'd avoid version 24 though, as it no longer supports plug-ins like Flash.
http://code.google.com/p/tenfourfox/downloads/list
SeaMonkey seems pretty fast also, with many options...
http://www.seamonkey-project.org/
http://www.seamonkey-project.org/releases/
The last version with Mac OS 10.4 and PPC support was SeaMonkey 2.0.14.
The last version seamonkey-for-ppc - 2.26 RELEASE - Mac OS X 10.5.x - PPC.
http://code.google.com/p/seamonkey-ppc/
PROJECT SITE:
https://sourceforge.net/projects/seamonkey-for-ppc
register for updates at the SourceForge seamonkey-for-ppc project page
https://sourceforge.net/projects/seamonkey-for-ppc
Might also look into iCab & OmniWeb versions.
The last really supported Flash for PPC was 10.1.102.64, but if it's for like Facebook or such, people have been fooling FB to think they have a leter version installed.
Texas Mac Man's Flash hack/post...
https://discussions.apple.com/thread/3599648?tstart=0
Flash player 11.1 hack on PowerPC - https://discussions.apple.com/thread/3558589?answerId=16990862022#16990862022
Might be later ones around also... saw 11.3 I think.
(If you are running a PPC Mac with Flash Player 10.1.102.64 and are having problems with watching videos on FaceBook or other sites, contributor Texas Mac Man suggests the following solution which fools the site into thinking that you are running the latest version:)
Download this http://www.steelbin.com/FPforFBPPC.zip to your desktop, unzip it, and replace the current Flash Player plug-in which is in your main/Library/Internet Plug-Ins folder, (not the user Library). Save the old one just in case this one doesn't work.