Apply to join the Nivea body products test panel
Bzzagent - you can get to test out some great products
Savvy Circle to test brands by Proctor and Gamble
Be aware when joining any of the above it is not just about being sent items and testing them - you have to blog, tweet, and facebook about them, you need to "spread the word". It is all about advertising your opinion. The more you do the more campaigns you will be invited to.