Adwords is great once you've know how to work it. Theres a fantastic ebook by Perry Marshall called The Definitive guide To Google Adwords. Everything you need to know to master Adwords is in that book. Its a good investment.

And like the other guys said, you want every page that you're proting to have an optin box on it. I wouldn't send anyone to any of my pages unless it had an opt-in box.