Cool! I've got the Indigo version, (basically the same except the colour), and it works very well with 10.4.
Not to put down your bargain, but I though I'd just mention it: I was at a live auction yesterday and there was a graphite iMac G3 there, without any peripherals - just the computer. I was too late to bid on it but apparantly it sold for £7! If only I had been there earlier...