Microsoft made the two hotfixes -- the reliability pack (KB 938194) and the performance pack (KB 938979) -- available for download on August 7. At that time, company officials said to expect Microsoft to make those collections of fixes available via Windows Update at "a later date."
To be fair, Microsoft never corroborated stories or blog postings that claimed the company's intention was to push the two Vista hotfix packs on August 14, Patch Tuesday.
I'm expecting we'll see those Vista fix packs on Windows Update real soon now. But they're not there yet.