I have hooked up everything from 8.3 to 10.1 mac OS's up to wireless routers, and all of them hooked in seamlessly. With the 9.x and lower, you would often need to install a set of drivers. Once those are installed, then in control panels - TCP/IP you should be able to select the card and then look for the wireless basestation.
Sorry, going off of my foggy memory and I don't have a mac handy. Check the base station and make sure that WEP is off initialy and that the IP address is something reasonable and DHCP is turned on. Once you hook it up and get everything running, set static IP's, enable WEP and use MAC address control - should keep the casual hacker out.
If you get really stuck, you might have good luck looking around
practicallynetworked.com . They often have excellent setup tips