I have a few early access codes to a network out of Singapore. They are called MyCube. Their big selling point is that you get the money from the ads on your page, not them.

To sign up:

1. Go to http://beta.mycube.com

2. Enter mctrevorg as the activation code

3. Fill out the form

4. Confirm in your email

5. You're now a super-early adopter!