Sun has released Update 8 for Java Runtime Environment 5.0. This is an extremely important update.
JRE has long been used to install malware as it contains numerous vulnerabilities which allow remote code execution. Another important factor is that JRE works with all web browsers. This means that a vulnerability in JRE will affect all browsers.
In my mind the most serious issue in JRE has finally been fixed. The problem with previous JRE releases was that they didn’t prevent a Java applet from calling earlier JRE versions. As previous JRE versions aren’t uninstalled automatically this creates a very dangerous situation. If machines have the latest version of JRE, but older versions haven’t been manually uninstalled the machines are still vulnerable.
So install the latest update ASAP. Either go to the website or update the program via the control panel.
There have been reports in the past that the updater in the Java Control Panel will say that the latest version is present, even though it's not. So double check that you have the latest version or go to the website.
P.S. If you uninstall all the older versions you’ll probably free up quite a lot of space on your hard disk.