It's easy. just follow the instructions below:

1) Vent sunroof
2) Unclip springs that hold inner headliner/sunroof panel to outer panel.
3) Push down inner sunroof panel so its flat.
4) Sitting in the cabin, apply firm pressure to both sides of inner panel and push backwards into roof. The panel should "snap" out of its holders and slide back into the roof completely. Just be careful the vent panel doesn't slip up and get caught.
5) Look up at the now exposed inside of the sunroof outer panel. You should see a rod across the middle, teh track runners, etc. You should also see a number of brass screws. I think there are four in the front, two on either side in the middle, and two on either side in the back. The last two are the ones that control the sitting position of the sunroof.
6) Remove all the screws.
7) Panel is now free. Lift up and away.

The seal sits on teh bottom lip and can be removed by pressing downon it. When you install teh new one put a little silicone in the crack and then hold it firmly. This will help make sure the new ring doesn't slide down and slip off slightly when you vent or move the sunroof.

good luck,
rt