Paul Thurrott posted a preview on Windows Vista Service Pack 1

After several months of silence, Microsoft last month finally revealed some concrete information about Windows Vista Service Pack 1 (SP1), which I translated into my Windows Vista Service Pack 1 Revealed showcase. If you haven't read that article, please do so now: This preview, which is based off of more recent beta code and an in-depth discussion with various people working on SP1 at Microsoft, builds off of that article, but provides more information and detail. Windows Vista SP1, finally, is a known quantity.

Inside Windows Vista Service Pack 1