Microsoft held a Windows Phone developer day in Japan on the 8th, and promised developers there they will each be getting a new Windows Phone 7 handset, as long as they intended to develop for the platform. Microsoft also said they would distribute by lottery free handsets to some of the developers who watched by Ustream.
Microsoft did not reveal details of the handset, but said this would be revealed later in the month. The handset is widely expected to be the HTC Mazaa however.
Microsoft announced in their blog the plan to give developers access to Mango by the distribution of handsets, but it is not clear if they will be giving out ROM updates to developers for existing devices, with the concern being that they will leave developers with devices that can not be updated to the official release when Mango does eventually come out.