I've just fresh installed Tiger (10.4.2) on my iBook G3 and there are something like 10 updates you need to do for Java alone before you can start using the internet properly.
Go to software update from the Apple menu and start updating. Repair permissions before and after each update from Disk Utility. Once you've done one update (sometimes requiring a restart) go back to software update and you will find the next update ready. Keep doing this until there are no updates left.
Once on 10.4.11 and with the Java all up to date you should be fine.
Also try TenFourFox browser for improved browsing on a PowerPC - http://www.floodgap.com/software/tenfourfox/
Some advice is to stick with Tiger on older machines as it is leaner than Leopard (OSX 10.5) but functions the same, and is potentially faster. This might be a helpful article: