Advertising in ezines and newsletters can be a tricky business if you go into it uninformed. This directory lists online publications and sources that have been in business for awhile and demonstrate a professional publishing regimen. I still suggest you have at least some direct contact with individual publishers before placing ezine ads with them.
I also suggest this! When placing ezine and newsletter ads from this list (or from anywhere else) you should TEST FIRST for response by placing the smallest and least expensive ad. The point is to minimize your risk, and be sure that someone is actually reading that ezine before you mortgage the farm.
You need to know which newsletter ads are producing results and which aren't. Otherwise you can fritter away your entire advertising budget in just a few days. Effective ad tracking bores some people to tears, but it's nothing less than "cheap insurance."
Which would you rather do ... go broke fast ... or track ad response and make money? (Dumb question huh?)
Here are a couple of good automated ad tracking softwares that I use.
AdTrackz
HyperTracker