The archives are in StuffIt 5.1 format, so you'll need the free StuffIt Expander to extract the archives.
CPUSpeedDisplay is free. Registration instructions are available online.
CPUSpeedDisplay is a basic utility, originally created to help me develop MyBattery.
This utility displays the current clock speed of your PowerBook. On older PowerBook models, the current clock speed can be changed to extend battery life. Newer models run at a single, fixed clock speed.
Version 1.1.1 has been updated to support the latest generation of PowerPC PowerBooks.
CPUSpeedDisplay will run on any PowerBook model, as well as any PowerPC-based desktop machine.