Some good news if you are in Germany and are on O2 and or Telekom. Actually, O2 seems to be getting the better deal.
In a tweet asked by Chris (@Fizi_zubi) to the carrier, O2 responded with (translated) "Mango is planned for mid September, so it won't be too long. Specific dates are not yet known.". Of course, mid-September is what we've been hearing about for awhile now, so it's a little unclear if they meant generally or specifically for O2--then again, O2 UK seems like they're just about ready to release Mango. But it's at least on their radar (and hey, they even know what it is!).
Next up is Telekom, which also knows about Mango. They're suggesting mid-October, which is not nearly as nice as O2's statement. However, it's a bit unclear if O2 and Telekom are talking about software updates to existing phones or new hardware.
To that end, no specific dates are given, but it's looking promising for the next few weeks for something to happen on the Mango front.