Java for Mac OS X 10.7 Update 1, released earlier this week, updates the software to version 1.6.0_29 and offers Mac OS X Lion users improved reliability, security, and compatibility.
For Snow Leopard users running 10.6.8, Java for Mac OS X 10.6 Update 6 is the update to turn to. It also updates Java SE 6 to 1.6.0_29, and delivers similar improvements to that of the Lion version.
What those improvements actually bring in terms of security is still unknown; when the information is available, however, Apple will most likely post it to its security updates page.
You can download these updates via Software Update on your Mac and Apple’s Support Downloads website.