Start Using Bitcoins:

You will need a wallet to receive coins and you can get one for free.
BlockChain.info Wallet - Its a Hybrid Wallet with many functions, and one of the best imo.
Bitcoin-Qt - Is a bitcoin wallet client, which was originaly started by Satoshi Nakamoto and is open source, but there are other alternative clients.
Easywallet -  This is an online Bitcoin wallet. It builds a unique url for access.
CampBX - The most secure US Bitcoin Trading Platform (Exchange USD <=> Bitcoins) 
         (Using the CampBX referral link will get you 10% lifetime discount on trades)




Getting some Bitcoins for free:

Get some bitcoins to start testing, how this all works, below are some services that offer you bitcoins:
BitVisitor -  Earn bitcoins in exchange for visiting websites, lasting 5 minutes or more!
BitHits - Daily BTC's payouts to your address
Daily Bitcoins - Send small amounts of bitcoins to your address.
CoinAd - Bitcoin giveaway faucet, also lists some offers.
BitCrate - Break a crate and get free Bitcoins!
Bitcoin Addict - Another Bitcoin giveaway site.
Earn Free Bitcoins - Earn bitcoins in exchange for visiting websites for a designated period of time. 
NetLookup - Send bitcoins straight to your wallet address.
Bitcoins4.me - Enter your Bitcoin address below to receive small amounts free bitcoin.
Bitcoin Addict - Another Bitcoin giveaway site.
Free.BTC.pt - Watch videos to earn BTC. See here for more info. (Need to register an Account).
CoinTube.TV - Earn Bitcoins for watching TV.
CoinURL -  Earn bitcoins by shortening links.
CoinVisitor - Earn Bitcoins for viewing websites and ads.
AnonymousAds -  Have a site or a blog? Then this is perfect for you.
BitBin - BitBin is a site you can use to store 'pastes', short text snippets, which can be (nearly) anything from code to chat logs. ( And earn bitcoins while doing it )
FeedZeBirds - retweet for bitcoins.
Seals With Clubs - Biggest Bitcoin Poker site, offers 0.05BTC away every hour to the winner of a freeroll (no entry cost whatsoever).
iWantFreeBitcoins - gives you bitcoins for taking offers. There are many free offers.
Paperco.in faucet -  Scan a QR code to reveal a MtGox code for 0.0007 BTC.
DragonTale - A casino site, but gives out small amounts for free that you can use to gamble with or withdraw to your own Bitcoin wallet.
Free Digital Money - Get unlimited Bitcoins sent to you instantly when you try new apps, fill out surveys, view advertisements, sign up for trial subscriptions, and much more!
BitcoinPlus - Generate Bitcoins leaving your browser tab open.
Strike Sapphire - Poker Freerolls, see more information here, enjoy.
CoinWorker - Earn bitcoins by completing short analytical tasks which can be done in your browser.
Rugatu - Ask questions with bitcoin rewards or become a bitcoin freelancer
Earn The Bitcoin - Earn free BITCOINS by completing FREE offers! You get points just for filling out the forms, ranging from 0.2 to 2.00 bitcoins each!
FreeDigitalMoney - gives you bitcoins for completing simple tasks, like watching a video or playing a game. Do not forget to change the receiving address to your own.
Bitcoin Street Faucet - will give you a one-time 0.01 BTC, if you have a phone that can receive text messages.
NEW FAUCETS UPDATED(25 May 2013): (No CoinURL Ads)

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The Bitcoin ME
Ten Bitcoin
El Bitcoin Gratis
Raw Bitcoins
FaucetBTC
Free BTC 4 ALL
Virtual Faucet
Sr Bitcoin
Green Coins





Spending Bitcoins:

There are lots of merchants accepting bitcoins, and everyday this list grows, from virtual bussiness to retail bussiness. But Im going to post some small ones where you spend little to no bitcoins :)
BitZino - Most famous bitcoin casino. (roulette, blackjack, slots, craps and quick poker)  -- all games are provably fair.
Seals With Clubs - Biggest Bitcoin Poker site.
Bitmit - buy and sell goods with bitcoin (eBay competitor)
BitcoinStore - Over 500k electronic products for sale (Amazon competitor)