Install System Preferences
System Preferences.app from a stock Mac OS X 10.4.9 installation runs as-is on the AppleTV.
It allows setting of many more screen resolutions if you connect to a standard DVI display, among other standard Mac OS X settings.
Copy the /Applications/System Preferences.app directory from your Mac onto the AppleTV in /Applications/
ssh to your AppleTV and run the following command:
open /Applications/System\ Preferences.app
Kill finder on your Apple TV if it is still showing and the System Preferences is not, using the following command:
kill $(ps ax | grep [F]inder | cut -c 1-5)