The next big launch in smartphone world is going to be Windows Phone 7 in Q4 2010 and details about smartphones based on the new OS have started leaking out. HTC’s first phone based on Windows Phone 7 will be called HTC HD7 and it will come with 4.3-inch WVGA touchscreen, 1GHz Qualcomm Snapdragon processor, 5-megapixel camera with dual LED flash, 8GB onboard storage, HD video recording and microSD card slot. The phone will be announced in Q4 2010.

In other Windows Phone 7 related news, Microsoft has announced that all five of the mobile network operators in the UN including Orange, O2, Vodafone, T-Mobile and Three will carry phones running Windows Phone 7 when it launches later this year. In addition, Windows Phone 7 will be available via the leading UK retailers The Carphone Warehouse and Phones 4u.

Microsoft hasn’t yet announced the launch date for Windows Phone 7, but it is rumored that official announcement should come by end of October.