Where is Linux Source Directory?

[Geoff Pitt]

Hi

I'm trying to set up wlan-ng on FC3 when I run make config it can't find 
the kernal source code at the default location and so gives an error 
message.  I've tried whereis linux at /. and it gives usr/include/linux, 
so I've tried entering this in the make config dialogue but still get 
the same error.  Can anyone shed any light on this?

Cheers

Geoff