There isn't a managed preference for this so I put the following in a login script. Here it is in case it helps anyone. Watch the word wrap
# Get user logged into console and put into variable "user"
user=ls -l /dev/console | cut -d " " -f 4
##
# Set iTunes to never check for updates
##
chown root:wheel /Users/$user/Library/Preferences/com.apple.iTunes.plist
defaults read /Users/$user/Library/Preferences/com.apple.iTunes.plist pref:130:Preferences | awk '{$15822 = "00010101"; $15813 = "00020000"; print}' | cut -d "<" -f2 | cut -d ">" -f1 | sed 's/ //g' > /tmp/1234.txt
a=cat /tmp/1234.txt
echo "defaults write /Users/$user/Library/Preferences/com.apple.iTunes.plist pref:130:Preferences -data $a" > /tmp/1234.txt
chmod +x /tmp/1234.txt
/tmp/1234.txt
rm /tmp/1234.txt
chown $user:staff /Users/$user/Library/Preferences/com.apple.iTunes.plist
