Best mailing list script/program

Need to add mailing list script to my site

[neveremail]

What is the best mailing list script/program that is free that I can put on my site to allow surfers to sign up to my newsletter?

[Webwork]

I'd run this past my web host so that you don't run into spamming issues, etc. Some hosts offer such services. Generally, if you are planning to get serious about using email to promote your site you want to think about outsourcing the process since getting past spam filters, getting blacklisted, etc. are matters of special knowledge and expertise.

[neveremail]

Well it is just a normal opt in mailing list where users can subscribe and unsubscribe easily. But yes it is difficult to get past spam filters