Here are a few email autoresponders that we recommend:
Aweber
Aweber is a very easy to use email service. This is what we use for our JamMob Newsletter. It is very easy to set up campaigns, and Aweber offers many nice looking email templates to help you look professional. It's just $1 to try it out for 30 days. Click Here to check out the site
Get Response
This is another very easy to use platform that we also use from time to time to send out promotions. It is also a very affordable option for the musician on a budget. Check out their site Here