AppleScript that points DNS settings to Google.

updatedns.scpt

set var to "Do you want to point your DNS to Google servers?"

set question to display dialog var buttons {"Update DNS", "Quit"} giving up after 5

set answer to button returned of question

if answer is "Update DNS" then
	do shell script "networksetup -setdnsservers Wi-Fi 8.8.8.8 8.8.4.4" with administrator privileges
	delay 3
	do shell script "dscacheutil -flushcache" with administrator privileges
	display dialog "Your DNS now points to Google servers." buttons {"Bye!"}
end if