Most email campaign managers – Constant Contact and the like, offer very nice campaign tracking tools. But I like to centralize my tracking and get everything flowing through Google Analytics, so I can closely analyze my conversions.
Here is an excellent overview of how to build your links in your email campaign software so your data gets tracked in Google Analytics.
http://www.epikone.com/blog/2008/11/04/email-tracking-with-google-analytics/
Warning: if you get queasy looking at urls with more than 46 characters, this exercise might not be for you!
