Something like this should do the trick from the command shell in Linux.
wget
http://www.kismetwireless.net/code/kismet-2009-05-RC2.tar.gztar -xzvf kismet-2009-05-RC2.tar.gz
rm kismet-2009-05-RC2.tar.gz
cd /pentest/wireless/kisme*
./configure --disable-setuid
make dep
make
make install