+1 for Constant Contact
I set it up at work for some marketing things we've done. Overall I've been really happy with it. My wife's company uses it as well. The basic service gives you nice metrics like being able to see who has opened the emails, who has clicked links, and who has forwarded the emails to friends.
Totally random fact about mass email. According to the marketing dept that my wife works in, the best time to send stuff like that is Wednesdays at noon. They have the most success with email opens, link click through, and forwards, for emails sent at that time.
I haven't tested the theory, but I've at least followed that rule of thumb with stuff at work, and we've had pretty good luck with it.
2004 UZJ100 - stockish for the time being.
Jetta Sportwagen TDI
Sold - 2010 Tacoma, lifted, locked, armored