earned income via surveys and online studies

I participate in surveys and studies for gift cards, and I've been informed that if I earn over $600 I will have to report it as earned income.

I have researched, and am very confused: I've seen 1099, W-9, C-EZ, even the standard 1040 using a 1099?

I'm also confused about what exactly the income from the surveys/studies should be reported as - awards and prizes? Other income?

I've been keeping records of all my payments (which are all via Paypal, so there are statements there as well); if anyone can help me with my numerous questions, it would be greatly appreciated.