Sprint service the only thing standing between you and a Motorola Xoom? Good news -- a tipster passed along an internal calendar showing an April 25th employee training date for the Honeycomb tablet, and while we're still taking it with a grain of salt, it seems like the real deal. If past products are any indication, it should hit Sprint stores a fortnight later, in early May, lining up nicely with those Xoom cases that were spotted in Sprint stores a week back. The Nexus S 4G also looks to be slo