Ok, basically, you just have a fresh install of SFC3, pick your favorite mod that may have a server up, follow the install instructions for that mod (most cases they require you to install either the 531 or 534B patches before installing the mod), and then install the access server patch which is located here at Dynaverse.net or at SFC3Files.com.
That should get you up and running. If not, just post back and let us know. We'll be more than happy to help you out.
Welcome back to the battlefield.