Hi PieEater,
I wanted to use my fingerprint reader too. I was searching an discovering. I've found few projects dealing with this. The bigges (I think) is fprint. I'm subscribed in fprint mailing list and I can tell it is still in developement mode and it can provide you just logging into system. There are no more other special program supporting it yet. But during last month it has few devel-jumps and this fprint project is growing up. We have to be patient.

BTW: Trust that finger print method isn't as secure as you think. Everyone can make copy of your fingermark. I will try it too in close future and I will tell you if my girlfriend can log into my pc throught fingerprint reader.
There is little HOWTO: How to fake fingerprints?
Interesting. Isn't it?