We know the Mac App Store is launching tomorrow, on January 6. We also know that Mac OS X 10.6.6 will be required to use the Mac App Store. Jim Dalrymple over at The Loop, however, confirms that according to his sources (and when Jim says "my sources tell me" he always means "someone at Apple told me") the Mac App Store is launching tomorrow at 12 PM ET, 9 AM Cupertino time.
According to my sources, the Mac App Store will be available at 12:00 pm (noon) ET on Thursday. That puts it at about 9:00 am PT where Apple is headquartered in Cupertino, Calif.
Of course, this means that come 12 PM tomorrow we should fire up Software Update and find a 10.6.6 update that, among fixes, will include the Mac App Store as a new system app. It is still unknown whether or not Apple will also offer a standalone Mac App Store download for 10.6.6 users on its website.
So anyway, get your credit cards ready: we're 23 hours away from the Mac App Store.