There are various websites I personally use to earn free BitCoins, and albeit that it is a relatively slow process if you only use one or two websites, if you decide to utilise as many websites as you can, you'll notice the mBTC stack up quite quickly!

Here are a list of websites that I use; at the time of writing they all work:

- http://freebitco.in/ 
This is a brilliant website, where all you have to do is type a captcha every hour and you can earn up to 0.667 BTC, yes BTC not mBTC.

- http://freebitcoins.me/
- http://www.thefreebitcoins.com/
- http://www.earn-free-bitcoins.com/
These three websites go hand in hand, as they all send your earnings to a temporary coinbox; they provide somewhat slow turnout, and can only be clicked once per half hour, so I time clicking on all three of these with the countdown on the freebitco.in.

- http://coinreaper.com/
Coinreaper lets you cycle through a large number of other free BitCoin websites, which means that you don't have to remember tens, or hundreds of links, you can just type in your bitcoin address and cycle through the pages.