Neowin spotted a rumor that Internet Explorer 10 may be launched together with Windows 8:
This information comes from Win7China, who also provided some of the first legitimate Windows 8 screenshots. Because they potentially have a solid source of information, this rumor holds a bit of weight. They also state that IE10 is already in Windows 8 M3, but we have yet to confirm that information.
The idea of including IE10 with Windows 8 seems logical. Considering that IE9 just launched, if the rumored Windows 8 launch days are correct, the browser would be well over a year old when Windows 8 finally ships to the consumer. Other than this little bit of information, not much else is known about IE10.