Mailing list script with referral tracking
 

Anyone know of an 'off the shelf' script that does the following:

douple opt in system
list members automatically get a referral url in the emails they receive from the system
If someone signs up to the list from their referral url, the referrer gets credited with points
text and html support

Thanks in advance

Also, I know this is a stretch--if there's a WP plugin that does this, let me know.

Bump for assistance :)

hosted or self hosted?

i think i know of a good hosted solution, but ill have to get the link when i get into the office tomorrow