Coincidentally, I've just bought a GeForce4 MX4000 myself. I paid for it before I was told that it wasn't actually a GeForce4, like you'd assume from the name (it's closer in performance to the GeForce2, apparently). So after getting some advice and looking around a bit more, I found this one: http://www.compuvest.com/Description.jsp?iid=210822

I'm arranging to return the MX4000, but if you still want one I'd be happy to sell it to you for about $25. (I'd go with getting the better card though. According to http://en.wikipedia.org/wiki/GeForce , the one I found is even better than the one Darien found, and at a comparable price. I don't know how accurate Wikipedia is, or about compatibility with older motherboards.)