Sedo is a German company that is well-known and well-regarded in the parking business. Their parking ads run on Google adsense and they give parkers a great cut of the revenue. Sedo also offers the most used domain auction system on the internet and even offer domain sale escrow services. For purchasing and auctioning, at least, they are the premier parking site today.
Sedo's RPM (revenue/1000 clicks) is somewhere between $24 and $80, so again you'll a large number of domains to make a significant amount of money (or one or two lucky ones that make a bundle). If you've got a domain that is otherwise unoccupied, however, it beats that 0% return you're currently getting.
