You have two choices. You can add an external USB optical drive, or, you can mod your Antec case to house a slim dvd slot-load player (what I did
)
To connect the drive, I used a
Slim ATAPI to USB 2.0 coverter (to save a SATA port)
More info can be found here:
Antec 900 Slimline DVD mod
The project wasn't too bad. I just dread having the tear the box apart, which is the easy part, and then put it all back together (zip-ties, etc)
Good luck with your choice. I had fun.