I installed the voicedial update today on my 1.1.3 phone and it really screwed things up.

I put my headphones on to make a call and when I was done I pulled them off and set the phone down on a stand to watch a movie. I did not get any sound from the speakers and when I tried to adjust the volume it said RINGER (headphones) when there were no headphones in. When I stuck the headphones back on it kicked my ipod function on and started playing the last thing I had listened to. After two reboots it was still kicking on the last thing I had listened to even after I had turned everything completely off and the volume hub still showed I had my headphones plugged in.

After going to installer and uninstalling the voicedial.app completely the problem instantly went away.