There is a free site that gives you a list of 500 survey companies. It's called wahmservice.com. They were by far my single greatest resource. Companies are listed alphabetically and there is a little blurb about each one so you can quickly scan them and see if they fit what you are looking for.
I am currently signed up with sixty-three survey sites or marketing research companies. The most important thing you can do is sign up with as many survey companies as you can. Some may only send you one survey a month, but if you are registered with one hundred or even two hundred, you will be getting a fair amount of surveys each day.
Check your e-mail every day and respond as soon as you can. Surveys fill up fast and may only be available for a short time.
Here are some of the top companies that regularly send me surveys(keeping in mind I have just started doing surveys regularly for about a month now): globaltestmarket.com (about 3-4 times a week), SurveySpot (about every three days); testspin.com (every other day), and mysurvey.com (once a week).
I also like Inbox Dollars. They are the only company where I do paid e-mails. They send about two e-mails a day for about 3 cents each. 42 cents a week for about two minutes of work-not bad! Also, they have a survey section you can go to and check out if you qualify for surveys to take without waiting for them to send you can invitation. They pay $1 per survey.