Instructions on how to associate with an AccessPoint under your operating system.
Windows
Windows 98, ME and 2000 each use applications shipped with your card that you should install and use. I will fill each of these out as I have time and cards 
Lucent / Orinoco / Wavelan
Linux
You should be able to define what network your pcmcia card connects to in /etc/pcmcia/wireless.opts, however some cards firmeware ignores this. To do it manually... iwconfig mode managed essid network_to_associate_with