I was also told that I would have to pay a technician to come out to replace the interior light bulb in my Advantium speedcook microwave, but after reading the instructions from the tip below, I was able to take care of it myself.
I ordered the parts online and , after unplugging and removing the unit from the cabinetry, I was able to follow the instructions as suggested by UNCLEMOE.
The only difference was that there were many more screws holding the cover in place. I removed all of the screws around the top and sides at the front edge of the microwave as well as the screws along the bottom of the sides and around the top and sides of the back panel. There is one additional screw that must be removed before the cover can slide back. This screw is on the right side of the microwave in a silver dollar sized indentation.
Oh, don't forget not to touch the halogen light bulb with your bare hands to avoid shortening the life of the bulb.
http://www.fixya.com/support/r650818-change_bulb_ge_microwave_jes1289sk01
It's crazy that GE should expect customers to pay a technician $100 each year to replace a simple lightbulb, but thanks to FIXYA.com I was able to do it myself in about 40 minutes with a little help to lift the unit.
as a side note, one of the screws was in so tight that the screw was stripped in an attempt to remove it. A little thing called GRABIT and a power drill took care of that problem in no time. check it out at 4GRABIT.com