Sun has released updates to address multiple vulnerabilities affecting the Sun Java Runtime Environment.
Sun recommends updating to Version 6 Update 7 which can be downloaded at:
http://www.java.com/en/download/windows_ie.jsp?locale=en
It is advisable to remove older versions of Java to remove the threat exposure. Uninstall details at:
http://www.java.com/en/download/help/5000010800.xml