Easiest thing is to set up your linux box to get it's TCP address via DHCP. This should also
set up your DNS settings. Set up your Linksys to serve up DHCP services (should be enabled by default). Then connect the two (make sure you have the proper cable type, crossover vs straight-through), and you should be good to go. The router should act as your DHCP client for your ISP, and should serve up a 192.168.0.x type address to your linux box. You can check out what address you get by doing an 'ifconfig'.