DVI to USB MAC convertor

Hi there! I have a Cintiq graphics tablet and I need a good DVI to USB convertor for my mac! Any good suggestions would be HUGELY appreciated! Many thanks!

err dvi to usb? what are you getting at? is this one of those backlit tablets with an lcd and a stylus? why would you need something like a dvi-to-usb convertor?

I have an old Imac G5 which does not have its own DVi port. The only way I can use my Cintiq 12wx is somehow using a convertor of some sort. I only have USB ports available. Its ridiculous that apple dont sell anything to support this. I also looked into a mac mini dvi to vga cable but the vga fitting does not fit on my old mac. I am not going to go out and buy a new computer just to use my graphics tablet.

I think this is what I'm after but i'm not sure if it will be compatible with my old mac and Cintiq tablet:-

NEW USB 2.0 to DVI Graphics Adapter Converter MAC PC on eBay (end time 15-Sep-09 12:38:02 BST)