i think it was really easy to do, but my headphone jack stopped working and the lcd lens never sealed down right, so some dust gets in from time to time.
ive done the 8900, Bold and the 8330. i felt the 8900 was extremely simple to do. the hardest was the 8330 since it required 2 different screwdrivers and the rubberized side pieces were very hard to maneuver around to get to the second set of screws.
it makes it seem a lot easier then i thought it would be and it mentions to try not to mess up that sticker in case something happens =) i just got my new houseing paid for i got a light pink set for like 5 50 off ebay so im excited if i can do it im a buy the silver keyboard next