This is a config for Cisco 1242 AP to get authenticated from MS IAS 2003. IAS 2003, MS DHCP and Cisco AP must be in same VLAN or LAN. Connect Cisco AP in the network. It will get an IP from DHCP. Make sure you reserve the IP in DHCP.
Log on the to AP using internet explorer using typical password i.e. Cisco (if you haven’t changed it)
provide SSID settings and check the broadcast in beacon
provide Radius IP and Radius secrete
Enable Wireless Radio 802.11A/G
Now add this client IP and shared secret in your Radius server. All done. Now XP/Mac client get authenticate depending on what you have set in Radius server say PEAP, Certificate…