Microsoft has sent out a cryptic invitation to select reporters for an upcoming event being held on Monday, April 12th in San Francisco. The notice itself doesn't mention much more than that the tag line "The phones are rumored to be labeled as "Sharp+Microsoft," have touch screens and slide-out QWERTY keyboards but none of that is official. Whatever they plan on announcing next week, chances are it has something to do with the mobile front -- feel free to speculate in the comments section. Meanwhile, Apple has its own event planned for this Thursday, where it is expected to introduce the next version of the iPhone OS.