Since then Samsung, HTC and LG have all released phones running the OS. The latest phones to be released on WP7 are from Nokia and are the Lumia 800 and forthcoming Lumia 710.
Apps from Windows Phone handsets are available from the Windows Marketplace, but with 50,000 apps to choose from it can be daunting to know what to download first, so here's our pick of the best Windows Phone apps to get your started. All are free Windows Phone apps, with the exception of a game you might be familiar with.
Are you a Windows Phone user? Which are your favourite apps, have you tried our top picks?