You can either organize the Netopia 2210N into bridge mode and utilize the WRT54G as a standard router attached to WAN port of the Linksys, or configure the WRT54G as a WAP.
In any situation, you would like to organize the Linksys BEFW11s4 as a WAP using the following configuration. This applies to the WRT54G as well if you decide not to bridge the Netopia.
Attaching two or more SOHO broadband routers mutually. Organize IP address of the secondary router(s) to be in similar subnet as primary router, but out of the range of the DHCP server in the primary router. For instance DHCP server addresses 192.168.0.2 throughout 192.168.0.100, I would allocate secondary router 192.168.0.254 as its IP address, 192.168.0.253 for another router, etc.
Stop DHCP server in the secondary router. Setup wireless sector just the way you would if it was primary router, channels, encryption, etc. Attach from primary router LAN port to secondary router. If there is no uplink port and neither of the routers have auto-sensing ports, utilize cross-over cable. Leave the WAN port separate.
This procedure avoids routing function (NAT layer) and organizes the router as a switch or wireless access point for wireless routers.