Apple has released Java for Mac OS X 10.5 Update 7 for Leopard users, updating Mac OS X's J2SE 5.0 to version 1.5.0_24 and Java SE 6 to 1.6.0_20 and delivering "improved reliability, security, and compatibility for J2SE 5.0 and Java SE 6." The only details given revolve around security fixes, so it's probably worth downloading this update even if you don't anticipate using Java applets much. Also note that J2SE 1.4.2 is no longer being updated and remains disabled in this update, which requires Mac OS X 10.5.8. (Free, 122 MB)
Set Time Zone Automatically in Snow Leopard
Frequent travelers may be interested to know that in Snow Leopard your time zone can now be set automatically by bringing up the Date & Time preference pane, clicking the Time Zone view, and selecting Set Time Zone Automatically. A progress spinner appears while Snow Leopard sends off information about the Wi-Fi signals in your vicinity and receives location data back.