Hi This thread should help regarding pictures and steps to take.
From memory you will have to remove the hard disk cage as one of the cage screw holes sits on top of the second of the two mounting points for the DVD drive (a casing screw goes through them both).
The only other thing retaining the DVD drive then is a screw hiddden under the long wiring harness that runs along the top of the DVD drive near the screen.
The DVD wiring connector connects to the mobo near the HDD mobo connector, pull up gently to remove.