Kismet can be found by googling "kismet_2007.01.R1b-1.0_armel.deb"
or more specifically here http://www.grahamdavies.net/bora_debs/

You will need to install the ncurses-base and libpcap dependencies, but they can be manually installed by adding the "Maemo Chinook" repository.
Details:

http://repository.maemo.org/
chinook | free non-free

You will need to enable red-pill mode to install ncurses-base and libpcap