I've had the phone for about 6 weeks now, and had this problem about 2-3 weeks.

Every time someone calls me, they hear a very annoying echo when they talk. Their voice is repeated loudly, twice. I don't hear it but they do and always complain.

This does NOT happen when I'm on my iphone headset or a bluetooth headset, just on the phone.

Any suggestions? ideas? I have a 4GB iphone on 1.0.2 running on Tmobile.