While there has been tremendous speculation that the Windows Phone 7.8 update would be released today, it's not going to happen. According to Terry Myerson, Microsoft's Corporate Vice President for Windows Phone, look for the update in early 2013.

The Windows Phone 7.8 update will bring the current crop of Windows Phone 7.5 devices (Samsung Focus 2, HTC Titan II, Nokia Lumia 900, etc.) as close to Windows Phone 8 as possible. Hardware restrictions prevent our old Windows Phones from making the full jump.