The documentary Hacking Democracy from HBO has been published on Google Video:
This follows another video demonstrating how to hack a Diebold voting machine.
Read Uninnovating Democracy for more information.
If these were ATM machines being sold to banks, the quality and security of these machines would have resulted in lawsuits, investigations, and firings many times over.
Funnily enough, ATM is precisely the core product of Diebold. Even funnier (or may be not), those can be hacked too.