According to the site Neowin.net, Microsoft has sent out invites to certain to potential beta testers.

In an email to beta candidates, the Windows Customer Connection Team has picked select testers for an early copy of Windows 7 SP1. The email read "You are receiving this invitation based on the quality of feedback you have provided on previous Windows programs", which promised early access to pre-release versions of the Service Pack.

The invite also confirms the Service Pack will be available in English, German, Japanese, French and Spanish. Microsoft is planning to release a public beta of Windows 7 SP1 by the end of July, & technical beta testers are expected to receive the beta by the end of June.

Windows 7 SP1 will include the usual hotfix patches, and RemoteFX which provides rich 3-D graphical experience for remote users. The service pack also will include a series of incremental updates, previously released on Windows Update for both Windows 7 SP1 and Windows Server 2008 R2 SP1.