Just found this when a friend ask for latest ISP deals going.
Terms and Conditions: This offer is available until 30 June 2010, on a 24 month agreement, to new Amnet broadband customers only. The $100 credit is not redeemable for cash. If you disconnect the service during the agreement period you’ll be charged the standard disconnection fee, see Amnet's FAQ for details. This offer is subject to our promotions terms and conditions.
EDIT: I think you get a free connection when signing up to 24 month plan anyway, but still the $100 credit is better than the $50 for their "refer a friend" deal, plus you get the first month free too.
Good deal on a quality ISP, does anyone know the process / downtime for moving from naked ii to naked Amnet.