So I copied the original AppleAirPort2.kext from Darwin and put it back in the extensions dir to start over. I thrn followed the directions exactly. This time all of the commands executed successfully so I rebooted. After bootup I still have nothing. How can this be, I have the exact same Dell D600 as several others who have gotten it to work. I did however find out that the error I was getting with the foo.c file was due to the fact that I was using TextEdit to make the file and so it was in RTF format even though I changed the extension. So I downloaded TextMate and made the file with it and no more errors. Now if I could only figure out why it's still not working. Help me please! This is the only thing keeping me from being a full time Mac person. Thanks!
For those with dells and perhaps others:
I have another d600 that didn't work at first. The problem ended up being a BIOS setting. Go into the BIOS and alt-p until you get to the page with the wireless settings. One of the settings turns the card on and off.. sorry, I can't remember exactly what it says and I don't have the machine with me now. The text to the right explains that even if it's off, the OS can still turn it on but that doesn't seem to be the case with osx. Enable the card in the BIOS and try again. If this works for you, please make a note of the exact setting and let us know.