ps2 to usb blue cube/ model m discoloring

[obj-c]

Where can i purchase the blue cube ps2 to usb adapter?
The only place I found them so far is amazon.
http://www.amazon.com/PS2-Keyboard-To-USB-Adapter/dp/B000BSJFJS/ref=sr_1_1?ie=UTF8&s=electronics&qid=1299454948&sr=8-1

And,

are IBM model m's known to discolor and turn yellow?

[kinkng]

I do have come Model Ms that seem to have yellowed.

I bought from cyberguys. They are a better place if you need to buy several (cheaper shipping).