Quantum security for networks

This article has been popping up over most of the security sites today. Basically, some researchers at Harvard, Boston University and BBN have created an optical network
that serves up web pages and basically acts like a regular LAN, by all accounts. The difference is that the simple act of eavesdropping on a communication disrupts it, so if your information makes it across the network, you know it remained private.

Actually, it's a bit more complex than this. Apparently all the data is encrypted using conventional symetric encryption and sent via a conventional network. The article implies that the photons are carried over a separate network, and are used to exchange encryption keys. This doesn't seem very practical right now, since we already have good algorithms for exchanging private key data over public networks. Also, good encryption is easy to come by, and fairly fast on today's hardware. Presumably the researchers in this project have bigger plans. I'm really looking forward to hearing what they are.