Can anyone recommend a free email optin form/plugin?

I want to put an email subscribers list optin form on my website. I could make my own but I figured why reinvent the wheel and it will save a bit of time. I'm sure theres loads out there. I've seen mail chimp but I'm not sure its free. I am looking at eMill optin right now and its free I think. Any recommendations?

See original post by broombroom