A (basic) finger print scanner could identify the type of print:
whorl, arc etc
and the ridge count
In terms of using as authentication, the only real way would be to use an applet of sorts to aquire from a fingerprint reader.
The reader could either send the data as recognised co-ordinates, patterns etc, or it could simply send an image.
In the case of the image, you'd need some complicated image manipulations to check. If it's simply point data, you're a lot luckier.
Either way, getting a secure way of attaching an applet to the finger print reader will be difficult. I think JAVA would be your best option.