To use kismet in Ubuntu 9.04 with Alfa Network Wi-Fi edit config kismet file:
sudo gedit /etc/kismet/kismet.conf
find “source” and edit it as:
source=rt8180,mon0,alfa
save, run wifi network interface (alfa) in monitor mode
sudo airmon-ng check kill alfa & sudo airmon-ng start alfa
(if your wifi card name is “alfa” or change name (ex.: wlan0, wlan1..))
Then run kismet:
sudo kismet