Double check that the wire to the Speedtouch (now) bridge is plugged into the WAN port of your Linksys. It sounds like it's plugged into one of the four LAN ports. The Speedtouch will only recognize one MAC address on the inside in bridge mode. Normally that would be the MAC of the WAN port of your Linksys. If you hit the LAN side instead it will take the MAC of the first device that talks to it and ignore the rest. Since a router will rewrite the MAC address for all packets crossing the router to it's own the Speedtouch normally would see only the router's MAC, but if you are on the bridged LAN side it will see each PC plus the LAN MAC of the router. I'm not quite sure how you are getting the PPPoE connection to come up, but unless there are some other connections in your network it almost has to be miswired. One other remote possibility is that you are using DHCP to address your PC's and the Linksys is configured to only hand out one address. You can check the addresses on your PC's using Start->Run->ipconfig /all. They should all be 192.168.x.y where x is by default 1 and y is different from device to device and not the same as your router, 0, or 255. If it's a 169.254.xxx.xxx you aren't getting a DHCP address assigned, and if it's something else you are probably getting a public address from your ISP, which should only happen to your router's WAN port.
I just noticed that you said you disabled DHCP on the router. Why ? If you manually assign the addresses they must be in the same subnet as the LAN port on the router, have unique last octets (last digit) and NOT 0, 255, or the address used by the router, have the same mask (usually 255.255.255.0), and have the gateway assigned to the LAN IP address on the router.
Edited by Orecomm, 14 March 2011 - 07:47 PM.