Well as you all know the Tiger is out. You can download Java 1.5 here and the Java 1.5 developer documentation here. The Java 1.5 installer does not make itself your default java though, so you should do two things:

1. In /Applications/Utilities/Java/JS2E 5.0, run the Java Preferences, and set your default Java version to be J2SE 5.0.
2. Open a terminal window and execute the following:

   cd /System/Library/Frameworks/JavaVM.framework/
   sudo rm Versions/CurrentJDK
   sudo ln -sf Versions/1.5 Versions/CurrentJDK
   

Now everyone's defaulting to Java 5.0 - huzzah!