Airprint Compatible Printers
I see this article was updated January 7th 2013 is the list of printers current & up to date?
iPad 2, iOS 6.0.2
It's as up to date as Apple had information as of that date. That's not to say that printer manufacturers may not have announced new models or released updates to existing printers and not informed Apple, so I would not consider that list as being completely all-encompassing and authoritative, no.
Regards.