If you're still using the Leopard version of Mac OS X and Apple's free Snow Leopard DVD offer didn't tempted you to upgrade, it's time to fire up the Software Update tool to get a security fix. Apple has released two pieces of software for users on 10.5.8 that are designed to combat the Flashback trojan that managed to infect a surprisingly large percentage of Macs before Apple patched it for more recent versions of OS X. The first is the "Flashback Removal Security Update" which will check your system for the trojan and remove it if found. It also disables the Java plug-in for Safari entirely, though users can re-enable it if they so choose. The second is the more straightforward "Leopard Security Update 2012-003" which disables older, less-secure versions of Flash and prompts users to update to the latest version. The combination of the two should protect you from Flashback and hopefully the changes from both Oracle will eventually mean that you won't need to wait as long for a fix should future Java vulnerabilities arise.