More Secret iphone Code

What a hack-y afternoon. Here are some more secret iPhone codes for you to enjoy. After realizing that the *3001#12345#* was a familiar Nokia code, I decided to spend some time googling for other phone codes that might work on the iPhone. These (mostly) do. There are more. Feel free to add your own to the comments.
*3001#12345#* and tap Call. Enter Field Mode
*#06# Displays your IMEI. No need to tap Call.

*777# and tap Call. Account balance for prepaid iPhone.

*225# and tap Call. Bill Balance. (Postpaid only)

*646# and tap Call. Check minutes. (Postpaid only)

*#21# and tap Call. Setting interrogation for call forwards.

*#30# and tap Call. Calling line presentation check.

*#76# and tap Call. Check whether the connected line presentation is enabled or not.

*#43# and tap Call. Determine if call waiting is enabled.

*#61# and tap Call. Check the number for unanswered calls.

*#62# and tap Call. Check the number for call forwarding if no service is available.

*#67# and tap Call. Check the number for call forwarding when the iPhone is busy.

*#33# and tap Call. Check for call control bars.