Thinkfinger working not spoiling the system on Debian/Lenny GNU/Linux OS for T43...

1. browse to http://thinkfinger.sourceforge.net/
2. download latest stable sources and untar them to <somewhere>
3. apt-get install libpam0g-dev
4. apt-get install libusb-dev
5. go to the <somewhere> directory and run ./configure --prefix=/opt && make && make install
6. add "auth sufficient /opt/lib/security/pam_thinkfinger.so" to the /etc/pam.d/common-auth
8. /opt/sbin/tf-tool --add-user <username> (optionally verify using --verify-user <username>)
9. try to login as <username> and enjoy :)

I hope it helps! -mjf