Can you tell me about windows phone 7 release date?

Windows Phone 7 is a mobile operating system from Microsoft. It runs on a number of mobile devices manufactured by Samsung, LG, HTC, Dell etc. From your question it is evident that you are most likely misinformed about the release of Windows Phone 7. Anyway, for your information, Microsoft released Windows Phone 7 almost an year ago, back in 21st October, 2011. Recently, Microsoft also released a brand new update to the operating system which is Windows Phone 7.5 dubbed 'Mango' on 27th September, 2011. If you are really looking for a Windows Phone device, it is better to go for a new 'Mango' based mobile phone. Interestingly, notable mobile makers like Samsung, HTC and LG have already announced their new handsets based on 'Mango' and they are going to available in market very soon, to be specific from the end of October onwards. Samsung has announced Samsung Omnia W, a pretty terrific handset by all means which will run 'Mango' from the beginning. HTC also announced their Radar handset having similar hardware specifications of Omnia W and also going to come with 'Mango' preinstalled. Although both the phones look pretty impressive in terms of raw hardware specifications. I would rather suggest you to wait at least till November for the official reviews to come out before making a move for any one of them.