Not the best news in the world for AT&T Dell Venue Pro owners but it's a start. Microsoft has updated its "Where's my Phone Update?" page and it indicates the Mango update for the Dell Venue Pro has joined the Focus 1.4 by entering the testing phase.
There is no telling how long it will take for testing to be completed. It is solely dependent on AT&T but we can only hope the testing moves to scheduling sooner than later. Once in the scheduling phase, the update should be pushed out within ten days.