Where can I find the latest java update for Mac OS systems prior to 10.6?
The Java updates for OS X come from Apple, not Oracle (that "owns" Java and provides downloads for Windows and Linux). In general, Apple doesn't seem to support OS X versions prior to 10.6 (that's something like an unofficial policy, they seem to support the latest 2 versions only), so in general you can't get official Apple updates for anything, including Java, for 10.5 and below. There were ideas about some open source substitutes for Java, but I am not sure what happened to them. Given the recent Java issues, Apple may decide to create and distribute Java update for 10.5, but I won't bet on that.