What kind of setup you have - are you using WEP or WPA encryption (and what kind of WPA, if any?), are you sure the wifi card is powered up (some laptops, for example, have a button to press that powers on and off the wifi functionality)? Which driver are you using, a native one or perhaps NDISwrapper or something else? Works best with a native driver I think..
This should show a list of available access points, if any (and if they broadcast their ESSID). If your wireless device is not eth1, change it accordingly (it can also be wlan0 for example).
Use this to connect to one of the access points you found above, or one whose ESSID you know. More: