Rumor has it that an announcement will be made on March 7 about the iPad 3, and that it will run on Verizon and AT&T's 4G network. According to The Wall Street Journal:
Verizon Communications Inc. and AT&T Inc. will sell a version of the coming iPad that runs on their newest fourth-generation wireless networks, according to people familiar with the matter, as the battle to cash in on big investments in mobile broadband heats up. Apple Inc. appears to be planning to announce the latest version of its tablet computer in the first week of March, according to another person briefed on the matter. Whether other carriers will also sell the device couldn't be learned.