Being a mobile PowerBook user, I always find myself needing to switch AppleTalk back and forth between Airport and Ethernet, depending on where my printer is, and what kind of network I'm on. I put the following simple bash script together to toggle between AppleTalk and Ethernet (assuming en0 and en1 interface names, respectively), making the switch a one-click process, and saving me lots of trips to System Prefs. Just copy and paste the following into a text file, name the file with the '.command' file suffix, chmod 755, then drop it on your dock, and click on it to toggle AppleTalk.

#!/bin/bash

## If appletalk is off when the script is run, it will be
## enabled on the following interface ("DEFAULT_IF", which is 
## set to Ethernet) and will report script feedback using the
## interface name ("DEFAULT_IF_NAME"), so modify these 2 variables
## to your liking:

DEFAULT_IF=en0
DEFAULT_IF_NAME=Ethernet

## no need to edit below here, unless changes are desired

echo 'Checking AppleTalk status...'
echo `appletalk -s` > TAT_TEMP_FILE

ETHERNET_STATUS=`cat TAT_TEMP_FILE | grep 'interface' | grep 'en0' | wc -l`
AIRPORT_STATUS=`cat TAT_TEMP_FILE | grep 'interface' | grep 'en1' | wc -l`

if [ $ETHERNET_STATUS = 1 ];
	then
		echo "AppleTalk is currently set to Ethernet."
		echo "Switching AppleTalk from Ethernet (en0) to Airport (en1)..."
		sudo appletalk -d
		sudo appletalk -q -u en1
		echo "Done! Switch was successful."
		rm TAT_TEMP_FILE
		exit
		
	elif [ $AIRPORT_STATUS = 1 ];
		then
			echo "AppleTalk is currently set to Airport."
			echo "Switching AppleTalk from Airport (en1) to Ethernet (en0)..."
			sudo appletalk -d
			sudo appletalk -q -u en0
			echo "Done! Switch was successful."
			rm TAT_TEMP_FILE
			exit
			
	elif [ -s TAT_TEMP_FILE ];
		then
			echo "AppleTalk is currently disabled."
			echo "Enabling AppleTalk on "$DEFAULT_IF_NAME" ("$DEFAULT_IF")..."
			sudo appletalk -q -u $DEFAULT_IF
			echo "Done! AppleTalk was enabled on "$DEFAULT_IF_NAME" ("$DEFAULT_IF")."
			rm TAT_TEMP_FILE
			exit
		
	else
		echo "Unable to determine AppleTalk status.  Now exiting..."
		rm TAT_TEMP_FILE
		exit

fi