Gore is endorsing Obama as I write this. Jon Cohn writes, "I'm here at a packed Joe Louis Arena in Detroit, where Governor Jennifer Granholm just introduced her two special guests: Al Gore and Barack Obama. I've attended more than my share of live sports events before. The roar was as defeaning as any I've ever heard." You can watch a live stream here:
Incidentally, it's no accident that Obama is holding this major event in Michigan. This is part of the effort to bring the party back together after the debacle that was the primaries.