I'm doing this and it mostly works pretty well, there is one problem though... I bought one of those tiny DVD drives that are made for use w/ laptops/netbooks and is powered only by the USB ports. Because of this the manufacturer decided to have the drive spin down almost immediately after any read is finished to save juice. Any game that streams data from the DVD is going to take issue w/ this and stutter while the drive spins back up to stream.
Prince of Persia plays fine in game, for example, but the game isn't trying to stream data while you're playing. Hit a plot point and the first second or two of the voice acting is usually dropped while the drive spins up. Once it's up to speed things improve to the expected performance.