Bulk Email Software - Opt In List

[urbanpimp]

I am developing an email list that I would like to send individual emails to on a regular basis. I would also like to create a an opt in list on one of my websites. Sort of like "click here to join our email list".
What is the best way to do this?

[Altheon]

PhpList is an opensource mailing script that has that functionality.

[peedy]

DADA mail