We have two XP machines and one Redhat 7.2 with RP-PPPOE. They are all connected to a Linksys etherfast Cable/DSL Router. Than that router is connected to the Alcatel DSL modem. We can't get all three machines to be on line at the same time. We can ping all machines, so we know they are on the network.
I am only a few weeks into my real networking experience with Linux and DSL routers but I just achieved this very thing.
All I know is that on the WAN side of my router I set up the info given to me by SWBell (they do my DSL) - mine was a static IP, I don't know what yours is... and on the LAN side I set up DHCP. Then on each machine I set up TCP/IP, NetBeui, and IPX/SPX and set them to automatically obtain IP from a DHCP server. On the linux box, it is also set up to get on a regular intranet. THE KEY IS that each machine is NOT supposed to be set up for DSL. Only the router gets the hint that you're on DSL at all. Each of the machines just know they're connecting to a DHCP server and are NOT repeat NOT set up for PPoE. Then the router will perform its switching functions to "split" the bandwidth. It took me a couple of weeks to figure this out but I finally did it 8-). In your router manual (mine was LinkSys) there should be instructions for setting up the PPoE connection for dynamic IP or the static IP (not PPoE) in the internal configuration of your router. Mine (LinkSys) you browsed to an internal setup page (192.168.1.1) and all the settings were there. No internet connection necessary to do this. Yours may be different if it is a different brand. Does this help?
Ah yes we have the same router. Just remember do NOT set up PPoE in XP. Let XP look for a DHCP server. There are two sides to set up in the router. WAN (DSL) and LAN (DHCP - or static for that matter, whichever you prefer).