Synovate is looking for product testers again. They are a great panel to be a part of. I've been with them for over a year and have been able to test cool new products and I've gotten paid for it. Its really fun. They only take a limited number of people at time. I'd definitely get on their list and wait for their emails. Go here to sign up.
Mindfield is my Husbands favorite Survey Panel. They are accepting new panelists as well. Go here to sign up with them.
NOTE: Neither one of the companies will bombard you with spam and email. In fact, when they do email you, its pretty exciting.