The fprint project aims to plug a gap in the Linux desktop: support for consumer fingerprint reader devices.
Previously, Linux support for such devices has been scattered amongst different projects (many incomplete) and inconsistent in that application developers would have to implement support for each type of fingerprint reader separately. For more information on where we came from, see the project history page.
We're trying to change that by providing a central system to support all the fingerprint readers we can get our hands on. The software is open source and in the long term we're shooting for adoption by distributions, integration into common desktop environments, etc.
Note: These instructions are intended for Ubuntu Hardy. I have not personally tried this on Gutsy, but if it works, let me know.
First off, remember that fprint is not entirely stable, and may not work all the time. A list of supported devices is here, and the list of unsupported devices is here.