Open the Script editor. and cut and paste this code.
Code:
set myIP to text returned of (display dialog "Input IP Address"
buttons {"Ok", "Cancel"} default answer "" default button {"Ok"})
tell application "Terminal"
activate
do script "telnet " & myIP
end tell
It will prompt you for an IP then run telnet via the terminal with that IP for you. If that is what you are asking, here you go.
