Review on Authsmtp by Mark Bennett

I like how you can use it to send emails through other services as well (like Gmail). This way if people are using Google Apps they don't have an issue with sending from one of their accounts that would normally be blocked by google due security concerns regarding "spam". You also dont need gmail addresses/emails setup in order run this feature which makes things easier since i'm not always willing nor able to get my users' permission's etc.. In any case its pretty easy once set up correctly so no complaints there! It does exactly what we needed - allows us access our mail account without needing another smpt server installed ourselves at least :).