Pomola Software has updated Mac Shutdown X (http://pomola.com/products_macshutdown/macshutdown.html), a Mac OS X utility for shutting down a Mac on a specified event or on a specified date and time, to version 1.6.1. The upgrade provides shutdown at the end of Chrome download and fixes some bugs.
Mac Shutdown X costs US$20. Version 1.6.1 is a free update for registered users. The software is Universal Binary so runs natively on both PowerPC and Intel Macs. It requires Mac OS X 10.5or higher.