Without prior indication, when starting iTunes on OSX 10.6 .4 I suddenly received the error dialog stating “This copy of iTunes has expired.” And Software Update states that all of the software is up to date.

The simple resolution is that a beta version of iTunes 9.2 that I installed did expire (so much for reading the fine print) and a re-installation of iTunes is required. iTunes can be downloaded on the apple site as a dmg file. When opened and the volume is mounted, run the iTunes.mpkg installer to restore the computer to a happy equilibrium. Fortunately, the beta version of iTunes does not need to be removed prior to installation.