Global Test Market

GlobalTestMarket
GlobalTestMarket has a very active survey division and requires participants worldwide over the age of 14. The views of those under 14 may be sought but the invitation will go to the parent for the child to complete.

You earn "marketpoints" each time you respond to a survey request - the closer you fit the demographics for the survey, the higher the points earned but you'll always earn 2 or 3 even if you don't qualify at all. A typical survey of 30 questions that takes approximately 12 minutes to complete will earn 60 to 80 MarketPoints. You can also earn extra points when you refer others. Each point is worth $0.05 and you need 1000 points to qualify for payment by cheque.

They seem to be fairly active. I'm receiving at least 2 or 3 surveys every week at present. For full details and registration form, visit GlobalTestMarket
Test and Vote
Test&Vote is slightly different from other survey sites I've come across in that you don't have to rely on getting invitations for completing surveys, but have several other ways of earning points or getting free items.