Newsletter Management

Hi,

I am looking for a good (advanced) newsletter/contact management system, with the following features. I am looking for something, which is preferably open source/free.

1. Ability to have different subscriber groups.
2. Can be linked to multiple websites.
3. I can manually make groups and add/remove addresses
4. Easy to integrate, does not require much programming knowledge.
5. Preferably has a support community
6. Recipient can unsubscribe from list simply by clicking on an "unsubscribe" link at the bottom of an email newsletter.
7. Sending an email newsletter to subscriber database via web-interface (by cut and paste of HTML and Text versions into a form).
8. Preferably running on PHP.
Any recommendations would be greatly appreciated.
Thanks