We have heard on a number of occasions that the Windows Phone 7 Mango update will be pushed out in September, but it is widely expected to be towards the end of the month.
Now, on the WindowsPhoneDev Podcast the Lowermilk brothers claimed it may be even sooner than expected, saying:
Next week is going to be a big week for Windows Phone. We have been told by various sources that Mango will be dropping and the final tools will be dropping for developers, so that would be interesting and something to look forward to.
The team have a pretty good track record, predicting correctly the developer beta of Windows Phone 7 Mango and also releasing the first screen shots of the new OS, so there is a good chance they are on to some thing.