From Bitcoin Wiki
- Get started buying bitcoins at Coinbase, Bitstamp or Cubits.
- Start by watching this 2 minute introduction video.
- Learn why it could be a good investment, or an objectively better means of exchange.
- Get a client and try it out yourself.
- For 1 BTC or less, use an online wallet that you trust.
- When storing large amounts of BTC, use paper wallets.
- Explore bitcoin history with a block chain browser.
- Ask a question at StackExchange or BitcoinTalk.
- Can I generate Free Money on my computer? (No, that's no longer possible.)
- Browse the FAQ.
- Where can I buy bitcoins? (Hint: You can't buy them with Paypal or credit cards)
If you're looking for how to get started with Bitcoin-Qt, this is the article you're looking for.