Comment Disable 3G, place next to amplified speakers (Score 1) 248
You can catch it in the act.
I just turned off WiFi and 3G, forcing my iPhone onto AT&T's 850 MHz 2G network.
Now any data transmitted triggers a very audible BRAPPPA-BRAP-BUZZ! through the speakers.
Turn up the volume and go to bed.
On EDGE it will take a long time upload all that data. It will be quite obvious if this is really happening.
Also, use cheap speakers, fancy ones might be shielded. I didn't even plug them into the phone.
-j