Ensure you have Java 1.5 Release 4 installed or later. This is freely available for OSX 10.4 (Tiger) but may not be installed by default and is not part of the automatic Apple Updater , it is available at http://developer.apple.com/java/download. Ensure you get the correct release for your Mac (Intel/PPC).

Download the jaikoz-osx.dmg from the Website

This should automatically mount itself as an additional drive.

Drag Jaikoz over to the /Applications link