OP - I changed mine for Osram Nightbreaker Plus, assuming you have halogen lights. Another tip is to mark a screw driver then give the height adjuster one full turn up. Sorry, can't remember which way moves them up (hence why you should mark the screw driver so you know how much you've turned it. I didn't :| )
Hope that helps, if not here's my thread from when I did it. Down the bottom of the first page is a post that will answer your next question about getting at the darned things...