The concept of get paid to do tasks is very simple to understand. You do tasks given by employers on the site and employers pay you. There are two sites which are legit and I have been paid by them numerous times.
MICROWORKERS– This site is one of the pioneers in this field. Microworkers accepts members from all countries and has a lot of tasks to do which is good for you. It accepts both alertpay and paypal as its payment processors. The minimum payout is 9$ which you can easily reach in a week working for 1 hour daily. I seriously recommend you to join this site. To join click here
MINUTEWORKERS– this site has same concept as microworkers. It gives you option to request a payout on 2$ but it charges a fee of 0.20$. it also has many tasks and if you are from US and UK then you will have more tasks to do. To join click here
TIPS TO INCREASE YOUR EARNING
First I will recommend you to make one extra yahoo email id to do the tasks which require to sign up. Make accounts on digg, facebook, reddit and twitter as there will be simple tasks to do which will require you to be registered on them. Only do those tasks which you can do completely otherwise your task will not be approved and you will not get paid.
I have written a series of articles on online earning and this is part3 of that series. To know more go here- part1, part2, part4,part5, part6