I have a 667 MHz PowerPC G4 – purchased in 2002 – which I don’t use often enough to warrant getting a new one. But I do need USB 2.0!! The computer is fine for what I need on the road – it works fine! Like the love and lore of an aging truck (yes I have one of those, too) I have been compelled to just tinker with the unit I have and put my money elsewhere (like into food). For this laptop I have done the obvious – upgraded the RAM to 1 GB – I believe that is the max amount. When it failed I replaced the original 30 GB hard drive with a 120 GB hard drive, and so on.
OK, the USB 2.0: I purchased a 2-Port USB 2.0 PCMCIA Cardbus PC Card from Amazon.com.