We have all seen the ads about doing surveys and earning cash for doing them. I myself was very nervous about doing them. I have found a couple sights that I do that have always paid in a timely fashion and I have had no problems with.
Opinion Outpost I receive emails from about 4 times a week with surveys to do. These surveys earn me points that I redeem for a check. I can cash out when I have 500 points which is equal to $5. You can sign up for them here: http://OpinionOutpost.com/join/7888485
I also do Pinecone Research however you can only sign up with them when they have openings. I will let you know when they have any openings.
Buzzback is another sight that has always paid me in a timely fashion, they also send you emails to take surveys. They can be found at http://www.buzzback.com/.
I am certain that there are other reputable survey sights however I just do not have time to do them all. If you have a favorite survey sight leave me a comment and let me know.