Can I talk on my iPhone and browse the Internet at the same time?
UPDATE: Yes, recent model iPhones can absolutely use LTE data while on a voice call. The original answer below refers to the first generation iPhone, released in 2007:
Unfortunately, no. The iPhone uses the EDGE network for data communications. EDGE cannot be used at the same time as a voice call is active as these two types of communications utilize the same channel.
3G capable phones can transmit data and voice simultaneously without interfering with each other.
Ryan Miller replied on Permalink
Not true. I have an Iphone 5 with LTE and I still cannot surf the internet or use network-connected apps while on the phone. It seems like a carrier-specific limitation.