http://www.bitcoin.org/

E se um dia os bancos se tornassem obsoletos ? A bitcoin pode ser o futuro do dinheiro.

Bitcoin P2P Virtual Currency

Bitcoin is a peer-to-peer digital currency. Peer-to-peer (P2P) means that there is no central authority to issue new money or keep track of transactions. Instead, these tasks are managed collectively by the nodes of the network. Advantages:

    * Bitcoins can be sent easily through the Internet, without having to trust middlemen.
    * Transactions are designed to be irreversible.
    * Be safe from instability caused by fractional reserve banking and central banks. The limited inflation of the Bitcoin system's money supply is distributed evenly (by CPU power) throughout the network, not monopolized by banks.

Bitcoin is an open source project currently in beta development stage. Development is hosted at SourceForge.

http://www.bitcoin.org/faq

What is Bitcoin?

Bitcoin is a peer-to-peer digital currency. Peer-to-peer (P2P) means that there is no central authority to issue new money or keep track of transactions. Instead, these tasks are managed collectively by the nodes of the network.
How does Bitcoin work?

Bitcoin utilizes public/private key digital signatures (ECDSA). A coin has its owner's public key on it. When a coin is transferred from user A to user B, A adds B's public key to the coin and signs it with his own private key. Now B owns the coin and can transfer it further. To prevent A from transferring the already used coin to another user C, a public list of all the previous transactions is collectively maintained by the network of Bitcoin nodes, and before each transaction the coin's unusedness will be checked.

For details, see the technical paper: Bitcoin: A Peer-to-Peer Electronic Cash System.
What can I buy with Bitcoin?

Check out the Trade-page. If you have a service provider you often buy from, ask if they'd like to accept Bitcoin as payment!
Where does the value of Bitcoin stem from? What backs up Bitcoin?

Bitcoins have value if they are accepted as payment by many.

When we say that a currency is backed up by gold, we mean that there's a promise in place that you can exchange the currency for gold. In a sense, you could say that Bitcoin is "backed up" by the price tags of merchants – a price tag is a promise to exchange goods for a specified amount of currency.

It's a common misconception that Bitcoins gain their value from the cost of electricity required to generate them. Cost doesn't equal value – hiring 1,000 men to shovel a big hole in the ground may be costly, but not valuable. Also, even though scarcity is a critical requirement for a useful currency, it alone doesn't make anything valuable. For example, your fingerprints are scarce, but that doesn't mean they have any exchange value.
How are new Bitcoins created?

New coins are generated by a network node each time it finds the solution to a certain calculational problem (i.e. creates a new block), for which an average solution time can be calculated. The difficulty of the problem is adjusted so that in the first 4 years of the Bitcoin network, 10,500,000 coins will be created. The amount is halved each 4 years, so it will be 5,250,000 in years 4-8, 2,625,000 in years 8-12 and so on. Thus the total number of coins will approach 21,000,000 over time.
What's the current total amount of Bitcoins in existence?

The number of blocks times the coin value of a block. The coin value is 50 bc per block for the first 210,000 blocks, 25 bc for the next 210,000 blocks, then 12.5 bc, 6.25 bc and so on.

As of October 30th 2009, there are about 26,000 blocks in the block chain, which means 26,000 * 50 bc = 1,300,000 bitcoins in existence. You can see the up-to-date number of blocks in the status bar of the Bitcoin main window.
What is a "block"?

A block is a unit which contains the information of the transactions made after the previous block, plus a transaction which assigns a new coin to the creator of the block. Blocks form a chain from the first block to the latest block. To create a new block you need to spend CPU time, which acts as an unbribable timestamp for the previous transactions. The average rate of block creation in the whole system is 6 / hour. For details, see the technical paper: Bitcoin: A Peer-to-Peer Electronic Cash System.

The block chain length is shown in the status bar of the Bitcoin main window. The number increases rapidly while your Bitcoin client is downloading the block chain from other nodes. After the downloading is finished, your node can start generating new blocks.
So your wealth is determined by the amount of CPU power you have?

No. There's a constant average rate of new Bitcoins created, and that amount is divided among the nodes by the CPU power they supply. The competition for coin creation will drive the price of electricity needed for generating a coin close to the value of the coin, so the profit margin won't be that huge. The easier way to gain a lot of wealth would be trading goods.

At the moment, though, you can generate new coins quite profitably, if you expect them to have real value in the future. If you choose to, be aware that Bitcoin is still experimental software.
Are my Bitcoins safe?

As long as you make backups of your Bitcoin wallet, protect it with a strong password and keep keyloggers away from your computer. You need to make a backup of your wallet after each transaction, as the old wallet backup will be partially or completely invalid.

If you lose your wallet or if some unknown attacker gets it and manages to break your password, there's no way to get your coins back. On the other hand, that is usually also the case if you lose your physical wallet.
Where can I get Bitcoins?

Find a Bitcoin owner and sell her something - MMORPG equipment, IT support, lawn mowing, dollars or whatever you can trade with her. You can also generate new Bitcoins for yourself by running a Bitcoin network node.

You can find currency exchangers on the Trade page.

dediquei algum tempo a minar e já ganhei 500€

http://bitcoin-portugal.com