Server 2003, dual lan, internet sharing problem…..again.

Hi all, just new to the site, getting loads of info.
Problem is, i have a dell server running 2003 with dual nic’s, Dns and dhcp installed and running 13 client computers from it. One nic for lan and one for internet. At the minute i have broadband access from an external network going to the internet access nic no problem. Question is, how do i share internet to the client pc’s through the server. Do i use a bridged network for the 2 nic’s or internet sharing or NAT. Am a bit lost. Thanks for any help.