When you put a local currency on the web, it’s no longer local and it’s called peer-to-peer currency:
Bitcoin is a peer-to-peer currency, meaning it is not issued by a central authority, like the dollar or yen. The money supply grows as the network grows and will max out at about 21 million bitcoins. But right now, you can purchase them online on the Mt. Gox currency exchange or an over-the counter market. They do not exist in physical form—only electronically, owned and traded by members of a special, anonymous peer-to-peer network. No third-party intermediary, such as a payment processor or a bank, needs to keep tabs on or process the electronic transactions.
Here’s an interesting video discussion of Bitcoin, though, be forewarned, the discussion is oriented toward illegal drugs.
I made a site to help newcomers get started. Check out How to mine bitcoins