Tension Software has updated Mac Restart X (http://pomola.com/products_macrestart/macrestart.html), a Mac OS X app that can restart a Mac on a regular basis or one time only at a specific date and time or at launch using it via Apple iCal or other applications — to version 1.6.1. The upgrade sports internal improvements.
Mac Restart uses the native Mac OS X Date Time Calendar control. It warns the user before a restart, showing a progress bar or jumping from the dock. And the software has a variable warning time interval adjustable in the preferences.
Mac Restart requires Mac OS X 10.4 or higher. It costs US$20, though version 1.6.1 is a free update for registered users.