Microsoft distributed a new build of Windows Vista's first service pack last week to its invite-only list of testers, according to bloggers armed with copies. But as is the norm, the version also leaked to BitTorrent networks. The 6.0.6001.16633 (longhorn.070803-1655) build weighs in at a relatively svelte 684MB, bloggers and message forum users claimed. The first Vista Service Pack 1 (SP1) beta, which leaked earlier this month to BitTorrent peer-to-peer file-sharing networks, was significantly larger -- more than 3GB -- and came as an .iso file that was, in effect, Vista with SP1 already added. Last week's build, an .exe file, updates existing Vista installations.  Vista updates -- such as security patches and other hotfixes -- are normally packaged as .msu files, however, perhaps indicating that 6.0.6001.16633 is not a direct step toward a public release of SP1.

Update: NEWS.com is reporting that Microsoft has now set a release date of the first quarter of 2008 for the first service pack update.