Just an FYI:
I went to download Classila for my clamshell iBook and noticed a link for TenFourFox (http://www.floodgap.com/software/tenfourfox/).
It is a PowerPC version of Firefox 4 and after using it all day seems quite zippy compared to Firefox 3.6.15 and Safari 4.1.3 on my TiBook G4 400mhz with 512mb of ram. I am quite pleased.
MaxTek