Microsoft has officially announced Windows Phone 8, the successor to its Windows Phone 7 mobile operating system. The new OS will be pre-installed on new phones from later this year.

Windows Phone 8 is described as being based on the technology core of Microsoft’s forthcoming Windows 8 PC and tablet OS, sharing its networking, security, media and web browser technology along with a common file system.

The new smartphone OS will support multi-core processors and higher screen resolutions than its predecessor, along with encryption, remote management, NFC transfers, over-the-air OS updates, a digital wallet and Nokia mapping. Developers will be able to take advantage of C and C++ support, in-app payments, VoIP calling and multitasking.

Existing Windows Phone smartphones won’t be able to upgrade to Windows Phone 8, although the new ‘start’ screen used by Windows Phone 8 will be available in a special Windows Phone 7.8 update to users running Windows Phone 7.5.

Microsoft also announced that the Windows Phone Marketplace now has 100,000 apps and games available.

[Windows Phone blog; Windows Phone Summit video]