Microsoft has just posted their security patch builletin for June. As usual all required patches for your PC can be found on Windows Update. Here"s a brief summary of the "critical" and "important" level vulnerabilities. (Read more for "moderate" level patches)
MS05-025: Cumulative Security Update for Internet Explorer (883939) Critical
Vulnerabilities exist in Internet Explorer, the most severe of these could allow an attacker to take complete control of an affected system.
MS05-026: Vulnerability in HTML Help Could Allow Remote Code Execution (896358) Critical
A vulnerability exists in HTML Help that could allow an attacker to take complete control of an affected system.
MS05-027: Vulnerability in SMB Could Allow Remote Code Execution (896422) Critical
A vulnerability exists in Windows that could allow an attacker to take complete control of an affected system. An attacker needs to authenticate to be able to exploit this vulnerability.
MS05-028: Vulnerability in Web Client Service May Allow Remote Code Execution (896426) Important
A vulnerability exists in the Windows Web Client Service that could allow an attacker to take complete control of an affected system.
A cross-site scripting vulnerability exists in Outlook Web Access for Microsoft Exchange that could allow an attacker to run a malicious script in Outlook Web Access.
MS05-030: Cumulative Security Update for Outlook Express (897715) Important
A vulnerability exists in Outlook Express that could allow an attacker to take complete control of an affected system.
A vulnerability exists in Windows that could allow an attacker to take complete control of an affected system. Microsoft Windows Interactive Training is not installed by default.