I will admit that I'm a free sample junkie. I love trying new things, and the word free can catch my attention faster than anything. I often request free samples through the internet. With that said, I'd like to recommend 2 websites that I visit (usually daily) to see if there are any new free samples available:
Deal Detectives - This isn't exclusively free samples, this site offers good deals in general, but they frequently have free sample offers. The site is updated daily. You can also use the search engine on the site (type in free) to see older offers.
Wal-Mart - Walmart offers about 4-5 free sample products at a time. They aren't updated daily. I haven't really discovered a pattern to their updates, it might be weekly, but I think it's just random.
So, for anyone else out there who likes to get free stuff, or try new products, you may find these sites helpful.