I did this last night. With my 3 year old twins eagerly hanging on my ares. It took me about 30 minutes. Of that, 25 minutes was spent trying to figure out how to separate the front of the kind from the back once all the screws were out. Had I looked for a teardown video, that would probably have gone smoother.
I could probably replace it again in 10 minutes.
The Kindle edges were pretty bardly marred by me int he process ("If I can't fix it, I'm going to throw it away anyway, so...."). It sits in a case anyway, so.. enh. :)