I have the same card, which runs on a very generic chipset, the good old NE2000, and uses the very generic Linux driver module: pcnet_cs. Since your router runs DHCP, you have a number of different options: Linuxconf, HardDrake, but honestly, these are utilities built for desktops where the hardware configuration doesn't change, and so get confused every once in a while. I hate to point someone to the command-line so early, but if you open up a terminal, su or login as root, just type:
Which is the Dynamic Host Configuration Protocol Client Daemon. Techically you should give it the argument of whatever network card, but it defaults to eth0, which is probably what the Linksys is getting allocated anyway.