DSL newbie blues

Until recently I had only a very simple two-machine network -- originally setup in OS9 -- that functioned quite well. There wasn't even a need to use a router, addresses, subnets or anything else, as all that was required was the Network Browser application that came with OS9. (This idea, BTW, came from David Pogue's tome *OS9: The Missing Manual*.) Whenever I needed to transfer items to the other machine (a beige G3) I'd reboot the iMac into OS9, transfer the file, and then go back to OSX. This sufficed given the infrequent need to perform such tasks.

Now, however, has arisen the need to set up a "real" network, and I'm flumoxed. What there is to work with is as follows:

• Mac OS 10.3.9
• iMac G3/333mHz
• AT&T Speedsteam 4100 DSL modem (for AT&T DSL service)
• (to which I need to add a) Linksys BEFSR41 Cable/DSL router w/ 4-port switch

Now, the AT&T person walked me through the setup for the DSL the first time around, and that appears to be working just fine. However, they won't support setting up a combined network on the Mac, being PC-centric. Nor does Linksys have anything on their site for using this router with a Mac. (The Apple guy at the local CompUSA told me that the Linksys WILL WORK with Macs, just that Linksys as a company won't support it.) Google searches resulted in nothing of substance in terms of tutorials.

What is needed is a step-by-step walk-through for setting this thing up right, starting with the basics (addresses, etc). Any helpful links, docs, or personal experiences would be appreciated.