Several of our readers have written in and asked how to make their iPhone stop sending them copies of their outgoing Gmail. Here’s how. Go to Settings -> Mail -> (Your Gmail account) -> Advanced. Switch “Use Recent Mode” from ON to OFF. Be aware that the first time you do this, you may end up sucking a bunch of old messages into your iPhone inbox. (I had about a dozen old emails which shows exactly how little I use my gmail account.) It’s a one time thing, though. After you get rid of those old e-mails by disabling “recent mode”, your iPhone will stop sending you those outgoing copies.
Read it here tuaw