Yahoo has provided an update on the planned search alliance with Microsoft due out later this year. The company says the goal is still to have the transition in the U.S. and Canada complete before the start of the 2010 holiday season. Yahoo says that in late summer, it will offer a window of several weeks in which advertisers can choose a time to initiate and complete their own transition. "Fact is, it isnt necessary to open a new adCenter account right now," Yahoo says.