Iphone thinks headphones are plugged in when they are not.

Sounds like the switch in the headphone jack is stuck.

Try inserting and removing your earbuds several times in a row.

This has been asked and answered many times. It is a very odd quirk of the iphone. Some say that resetting will correct this. Most seem to say that plugging and unplugging the headphones several times in a row will clear this up.

I hope this helps you.

A Reset is different from a Restore with iTunes.

To do a Reset, press and hold the Home button and the Sleep/Wake button simultaneously until you see the Apple logo and then release - ignoring the slide to turn off prompt when doing so.

A Reset is similar to a computer restart, and does not affect any data or settings.

After trying all kinds of methods, the only one that worked for me was this one:

http://ifoneheadsetjackfix.blogspot.com/

I hope it helps you understand why this problem happens.

I don't want to open my iPhone but thanks for the tutorial anyway. For the time being it works for me after blowing hard into the headphone jack inlet. Don't know how long it will last.

i have not tried any of the above yet, but when i downgrade the firmware to 1.1.1 it works fine, but any other version makes the phone think it has the headsets inserted.