Also, be careful of emails going around that warn you to install this update. This is fake.
http://isc.sans.org/diary.html?storyid=2946&rssAn explanation:
Microsoft Security Bulletin MS06-4
Cumulative Security Update for Internet Explorer (113742734)
Published: June 3, 2007
Version: 1.0
Summary
Who should read this document: Customers who use Microsoft Windows
Impact of Vulnerability: Remote Code Execution
Maximum Severity Rating: Critical
Recommendation: Customers should apply the update immediately.
Red parts, wrong info.
MS06-4: Wrong format. It should read MS07-004. MS07 stands for the year.
113742734: Too many numbers. Microsoft KB (Knowledge Base) article doesn't have so many numbers.
June 3, 2007: Wrong date. It has been first published on 9 January 2007, and has been updated on May 29 2007.
Version: Wrong. It's at version 3.
Exact article is here:
http://support.microsoft.com/kb/929969/en-us