Yes and No

Yes, it will work, but no, not like you think

You can connect a regular PC DVD rom drive to the xbox, but you must leave the original xbox drive connected as well!
What you do is install a power splitter from the HD so you can power the dvd rom drive, which I believe you set to Slave or Cable Select.
Then you remove the IDE plug from the xbox dvd drive and use that on your pc dvd drive, BUT YOU MUST leave the xbox drive plugged in to power (the funny stranded yellow cable), or your xbox won't boot right.
BTW, I've never actually tested this with retail games, so there is a chance they won't work...
I guess someone will let us know