I found this video on YouTube http://www.youtube.com/watch?v=D65x8G1f6AI

pulling the assembly out looks fairly simple, but can I just change the bulb? Anyone know the part number? I got thousands of results on eBay for boxster headlight bulb but I haven't the slightest idea which one I should buy.

It's an H7 bulb for the headlight. You have to pull the assembly out to change the bulb, it's a fairly simple procedure.

Thanks for the response. I got 1800 results for boxster headlight bulb h7. Which one's the original and does anyone know what size hex that tool it?

H7 is a type of bulb, any H7 bulb should work. Not sure of the size of the hex tool but here's another really good write up on the procedure. I would replace both at the same time so your lights look similar

http://www.bombaydigital.com/boxster/projects/headlamp/

Well I just totaled the boxster so this should be fun...