The panel between the dash and the door just prises off. Use a fuel/credit card to get under it nearest you and not the door frame. There's about three clips. Don't worry, you won't break anything. The drivers side trim around the air vent also comes off really easily too. That might give you better access. Also, if you need to get the A pillar trim off so you can get into the corner that's not hard either. There's a knack to putting it back though!
I had all these pieces off about a hundred times while trying in vain to track down my rattle. If I can do it I'm sure you can. Some pics here http://www.e90post.com/forums/showpo...03&postcount=1