Dlink D520

Operating system FC6

installed madwifi packages
rpm -qa | grep madwifi
kmod-madwifi-0.9.2.1-1.2.6.18_1.2869.fc6
kmod-madwifi-kdump-0.9.2.1-1.2.6.18_1.2869.fc6
madwifi-0.9.2.1-1.lvn6

I am using wep for security.
Related documentation configuring madwifi with wep

iwconfig ath0 essid any
Put your network name instead of any...
iwconfig ath0 key XXXXXXXX
Put your security key instead of XXXXXXXXX
dhclient ath0