Apple has announced that it will be keeping all 164 of its retail stores open until midnight tomorrow, June 29, for the launch of the iPhone. Also, purchases of the iPhone will be limited to two per person, on a first come, first served basis. Beginning Saturday morning, free, in-depth workshops on how to get the most out of iPhone will be offered throughout the day at all stores. Support for the new handset will be provided at the each store’s…