I'd heard that the XBox doesn't support force feedback (which seems strange, but also seems to be true based on the software out there). You might consider picking up a used PS2 (and the upcoming GT4!).
Anyway, here's what I found with a little Googling:
A used one for ~$30 from GameStop:
http://www.gamestop.com/product.asp?product_id=900507
A CNet review of a "NASCAR" wheel for Xbox:
[url[http://shopper.cnet.com/Logitech_NASCAR_Racing_Wheel_for_Xbox_wheel_and_pe dals_set/4014-3146_9-31223459.html?q=[/url]
A really slick-looking one on xbox.com:
http://www.xbox.com/en-US/hardware/3...acingwheel.htm
Hope some of this helps. I tend to stick to PS2 for racing, Xbox for everything else, but that's just me.
Chuck