I just did a search and this small tidbit appears to be new info for this forum. The short story is that sliding a piece of plastic inside a dead power button can revive it. (Read on for the more verbose story.)

My launch-day Pre's power button stopped working a few weeks ago. I could tolerate this until I started having either software or digitizer problems. Since it was getting worse, I brought the phone into the nearest corporate store that seems to have good techs. Of course the digitizer was not misbehaving in the store, so I'll debug that if it reoccurs. The tech was able to fix the power button by sliding a strip of plastic inside the switch. While it might seem like a "shoemaker" fix, I'm perfectly happy with it if it stays fixed. I asked them to replace my battery (because the old one had been drained a few times too many and doesn't hold a charge for long anymore). The tech said the battery passed the tests, but replaced it when I said it really was a problem. (I don't complain much, so I think she was happy to keep me happy.) Anyway, I just wanted to mention the fix in case anyone else wants to keep their Pre or to nurse it along (perhaps after the warranty runs out).