Check out your local Fry's AD in LA Times, it has a Cendyne 16x DVD-ROM drive for $17.99 after a $20 MIR. This seems to be a pretty good deal for an internal drive.

http://latimes.p2ionline.com/shoppingchannel/data/images/52181_206015.jpg

http://latimes.p2ionline.com/shoppingchannel/rop/