I was messing around with an iBook G4 a year ago or so, and yeah things work "fine". You need to update the certs but otherwise it just works. I mostly used it to sync an old iPod nano since it's the only mac I have and I refuse to use windows, but browsing the internet "worked" on websites that aren't too demanding. I got 4chan to work fine, and youtube loaded but the playback was terrible.