I found that Ramjet sells both memory sticks (2x512mb for $199) but their instructions for installing the internal ram was removed from their web site by Apple's request with new instructions to take your iMac to a service center for installation. I can do this on my own with some simple instructions. Just looking for any help from someone who's done it already.
I just got a new iMac G4 17", really nice, but I have reached the memory limit a couple times already with only 256MB, it's real evident that performance would be much faster with more memory when I get several applications open at once.
Gene