More details emerged on Windows 7 SP1 today, which seems to mainly concentrate on rolling up previous patches and hotfixes rather than including new features.
http://www.computerworld.com/s/article/9172738/Microsoft_announces_Windows_7_SP1
Computer World have more information:Two weeks ago, a Web site that has regularly predicted release dates for Windows and its service packs said that Microsoft had dumped plans for a 22-month development cycle for Windows 7 SP1, and instead might deliver the upgrade in the fourth quarter of this year. At the time, Microsoft declined to talk about Windows 7 SP1, with a spokeswoman saying, "We do not comment on rumors or speculation."
If Windows 7 SP1 follows the pace set three years ago by Vista SP1, the fourth quarter is a good bet.
After much hemming and hawing, Microsoft admitted it would create SP1 for the then-new Vista in late July 2007, announced a schedule in August, seeded an invite-only group of testers with an early build in September, posted a release candidate for public download in December 2007 and formally launched SP1 in mid-March 2008. From start to finish, the Vista SP1 process lasted just over eight months.
http://www.computerworld.com/s/article/9172738/Microsoft_announces_Windows_7_SP1