In its security bulletin summary for June 2008 Microsoft has published three updates for new critical vulnerabilities in its operating systems / applications, as well as three imprtant and one moderate.

Critical is Microsoft’s highest vulnerability rating.

A summary describing briefly the vulnerabilities is available from Microsoft’s Security Bulletin Summary for June 2008.
From this page you will also find links to more detailed information in Microsoft's Security Bulletins MS08-030 - MS08-036.

The critical updates address the following issues:

• One privately reported vulnerability in Bluetooth Stack Could Allow Remote Code Execution
• Two privately reported vulnerabilities in in DirectX Could Allow Remote Code Execution
• One privately and one publicly reported vulnerabilities in Internet Explorer

Updates that fixes the vulnerabilities are available from Windows automatic update mechanism for systems that support this. Alternatively, one may download updates from http://windowsupdate.microsoft.com.  

Norman advices all affected users to download the security updates as soon as possible, to be protected from potential exploits.