Promoting with email

Hi, I just come up with the idea to promote clickbank products throught mail, well I'm probably not the first one . Lets say that I got a list of 5000 emails, what do I do? Have you used this method before, how did you do?

there are specific programs and scripts allow you to send huge amount of emails at once, Gmail and Hotmail and those companies allow you to send only 500 emails per day..