I have found an excellent tool to do that with. The Ad Xchange gives an excellent opportunity to test subject lines, and text that you might use for classifieds or safelists. It has a readership of close to 5,000,000, so it's great exposure and you can monitor your traffic from the back office. If you aren't getting any traffic-you know your subject line is way off. If you are getting traffic but no signups or results (contacts) then the body of your ad needs work. The best thing is you can post as many as you like, so you can keep at it until you get results. Then you can use that ad in your other medias. I encourage you to give it a try, it's really working for me.
Did you read my article on Hurricanes and Satellite TV? It's a test of sorts but I would love to have your feedback.
Have an awesome day and God bless you!