Apple has released Java for Mac OS X 10.5 Update 7 (http://support.apple.com/kb/DL971) and Java for Mac OS X 10.6 Update 2 (http://support.apple.com/kb/DL972). The first is a 122MB download and requires Mac OS X 10.5.8. The second is a 78MB download and requires Mac OS X 10.6.3.
According to Apple, Java for Mac OS X 10.5 Update 7 delivers improved compatibility, security, and reliability by updating J2SE 5.0 to 1.5.0_24, and updating Java SE 6 to 1.6.0_20 for 64-bit capable Intel-based Macs. J2SE 1.4.2 is no longer being updated to fix bugs or security issues and remains disabled by default in this update.
Apple says Java for Mac OS X 10.6 Update 2 delivers improved compatibility, security, and reliability by updating Java SE 6 to 1.6.0_20.