Seeing as mine went out recently....I figured I'd bring this back up, post the instructions for changing it and move it over to the "How-To & FAQ" section seeing the frequency of the problem.
Thanks to Molson for these instructions:
1) Resistor is located next to firewall on passenger side, in part of the blower motor plastic housing assembly, on the downside part of the assembly that is toward the passenger's feet.
2) To get to it, you will need a 7/32 " socket. You will need a universal socket adapter. Trust me... you will need a universal socket adapter.
3) You will need to either be skinny, or hire a ten year old boy who can work tools and can bend his spine funny. (Actually, you can do it). You will need to open the passenger door, and lay on your left hip with your upper torso on the passenger floor.
4) Look up toward the fire wall. LOOK UP! You will see wires feeding the resistor via a connector. You will see two bolts holding the resistor in the housing.
5) Bingo! There you are!
Part #: 15359314
GM LIST: $23.88
OUR PRICE: $11.94