Apple is expected to name Verizon Wireless as one of its carriers with its anticipated unveiling of a new tablet device on Wednesday, sources told The Post. That means Apple head Steve Jobs will probably introduce a Verizon iPhone, ending AT&T’s exclusive hold on the hot smartphone. “It’s almost a certainty,” said telecom consultant Dunston Almeida. “AT&T losing iPhone is the worst-kept secret on Wall Street. The only question is whether Apple announces a Verizon iPhone this week.” They went on to add what everyone has known since forever: Apple has been “extremely frustrated” with AT&T’s iPhone service, which regularly drops customers’ calls, especially in high-traffic New York and San Francisco, said a source close to AT&T. Don’t get your party hats and streamers out just yet.  You’ll have to wait until June. AT&T’s exclusive deal with Apple ends in June, sources said. Then there is poor AT&T who’ve apparently been unable to gain customer growth outside of iPhone users.  What will they do when iPhone users have other carrier options?  Drop prices?  Improve service?