Paperback Swap (see link on my sidebar) a new site:
SwapaDVD! What a great way to get rid of your old DVD's and get some new ones. You sign up, put ten DVD's in the system and get a credit-you order DVD's by credits and that's it. If someone orders a DVD from you, you pay to ship it and when they receive it, you get a credit-shipping generally costs $1.98 first class mail or $2.13 media mail, depending on the case it's in, etc. You can even swap credits from your Paperback Swap account.
I've been a Paperback Swap Member for over a year and love it! I signed up for SwapaDVD today and ordered my first DVD and one I listed is on someone's list. Yay!