As we had previously informed, Microsoft has posted their security patch bulletin for August today, including some patches that have been categorized as 'Critical'. You should be able to get this from the Windows Update site, or as standalone versions from our OS Updates page (not up to date yet).
Here's a brief summary of the 'critical' and 'important' level vulnerabilities, as reported by our friends at Neowin:
MS05-038: Cumulative Security Update for Internet Explorer (896727) Critical
Vulnerabilities exist in Internet Explorer, the most severe of these could allow an attacker to take complete control of an affected system.
MS05-039: Vulnerability in Plug and Play Could Allow Remote Code Execution and Elevation of Privilege (899588) Critical
A remote code execution vulnerability exists in Plug and Play (PnP) that could allow an attacker who successfully exploited this vulnerability to take complete control of the affected system.
MS05-043: Vulnerability in Print Spooler Service Could Allow Remote Code Execution (896423) Critical
A vulnerability exists in the Print Spooler service that could allow remote code execution.
MS05-040: Vulnerability in Telephony Service Could Allow Remote Code Execution (893756) Important
A vulnerability exits in the Telephony Application Programming Interface (TAPI) service that could allow remote code execution.