As with any Windows release, Microsoft engineers start tackling bugs as soon as the OS becomes available, so reports detailing plans for Windows 7 SP1 aren't surprising.
The most recent Windows 7 SP1 rumours come courtesy of Wzor, which detailed that a beta release of SP1 is expected to arrive sometime in January of 2010, possibly around the same time as the annual trade show CES.
Wzor went on to detail that beyond the relatively viable initial beta in January, a further two beta releases could be expected throughout the first half of 2010. Futhermore, Wzor believes that two release candidate updates will add to the service packs development roadmap, before the final version arrives.
The completed service pack will then be made available to manufacturers in the late summer, with the concluding build being made available to end users via an update in the fourth quarter.
The majority of this report can be classified as just purely speculative for now, however Wzor has released an image showing the alleged folder stucture of SP1 to assist in solidifying the claims. In addition to this, Wzor have become somewhat infamous for various leaks of Windows 7 during its beta stage.
Microsoft has yet to comment on the legitmacy of this report.