They usually tell you to turn it off as soon as they push out from the gate. They don't seem to be too strict about it though. I've been on several flights where people just keep chatting while we were taxing, and the flight attendants never said anything.
Regarding phones working at altitude... I've used my treo to check email while in flight.
so i'm listening to the podcast as i type this and one of the mythbuster guys said that they couldn't use a cell phone while taxiing...i feel like almost every time i'm on an airplane i am told, while taxiing, that i can use my cell phone.
any insight? am i just remembering wrong (i don't think i am but who knows)?

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