I reset my iPhone (all content and settings) and I noticed that my speakers don't work anymore!? I don't get any sound when I play a video and the volume is all the way up. I don't have ring silencer on. Any ideas?!
Alright I fixed my problem. The problem seemed to be 1.0.2 restore file I downloaded. I re-downloaded it from another site and it worked great! Restored my firmware and all my problems are fixed!
PS: Sorry about the re-post, I had an issue with my internet connection failing and I wasn't sure whether it posted.
BTW - Since updating to 1.1.1 I have had that issue quite frequently. My phone occasionally thinks that a headset is plugged in when there isn't one and disables the internal speakers. This even persists after a reset. A quick work around is to plug-in a headset and disconnect it to get the phone to recognize the problem. You may need to do this a few times to get it to re-enable the internal speakers.
Wow, this worked for me too. I was traveling today and missed about 6 calls b/c my speaker quit working. Must have been while I was on the plane listening to tunes.
I was ready to call Apple, but did the fix you posted and it now works fine (and the Q-Tip is dirty).
Apple needs to do something with that sensor. Everyone, at some point, will have this issue.