I had a HLN617W, and got to watch the service guy replace the color wheel twice before giving up and returning the set. Basically, you remove the back panel (~10 screws), disconnect about 5 connectors (mostly fan wires), take the DVI logic board loose and lay it out of the way, remove 4 screws and slide the light engine out. Probably a 30 minute job end to end.
Unfortunately, the service technician has to drive to your house with all his tools (electric screwdriver), replace it, and drive back to the shop. This is more expensive (for Samsung) than having a truck driver drive to your house, pick up the TV, haul it around in the back of his truck while he picks up all the other dead Samsungs in the area, drive back to the shop. Then the technician spends his 30 minutes. Then the truck driver hauls the TV (along with all the other repaired units) back to your house.
I would also suggest you have a way (a DVD/CDR with a white picture works well) to display a fully white screen on your TV before it is picked up. Look for any smudges or discoloration on the screen, and document their locations. After you get it back, check again. After the first colorwheel change (for noise) a smudge appeared on the screen, after the second colorwheel change the smudge had moved to a different location. So make sure it is perfect before accepting the repair as complete!