Hi,
That's actually my listing, and the item actually is already sold. Sorry!
I do expect to be getting a tray-loading drive (an exact replacement for the original in your 500MHz iBook) in a few days, but AFAIK that one's only a CD-ROM drive, not a CD-RW/DVD one.
FYI, the slot loading drive will work, but your 500Hz iBook uses a tray-loading mechanism, so the bezel won't line up. You'd have to remove the outer bezel of the slot-loader, or else hack up the side of your 500MHz iBook.
It's only a cosmetic issue, but (depending on your aesthetics) a pretty significant one.
Unfortunately getting an affordable replacement drive for the trayloading iBooks that adds CD-RW/DVD capability and looks factory is a giant PIA.
M