You would need to set up the client side first, to do that check out
and for a server you'll need http://www.mcportcentral.co.za/index.php?topic=2535.0, Put they net folder in your tekkit.jar for the server.
I've been having connection issues though, I'm not sure if it's a ram problem or something else. Myself and others get timed out and have to retry 3 or 4 times to get in. If anyone has input/advice I'll be happy
Thanks