I found this article which speaks about a Russian firm which developed a tool to use NVidia GPU (up to four) to decrypt WPA or WPA2 encryption systems (bruteforce method).
Here is the product: ElcomSoft Distributed Password Recovery.
Conclusion? Wi-Fi protections are not sufficient enough to ensure confidentiality! Always use other encryption mechanisms over your Wi-Fi networks (VPN, SSL, SSH tunnels, …)