How can I achieve this? Survey -> email

Alright guys, here is the deal. I need to setup a survey on my page. People will click on link, it will bring up a survey and they would have to fill it. Only after they complete it, they can sign up for the newsletter - basically giving me their email.

Since I've never done anything like this and I am not sure if there is such a service, I came here for help. How can I do this? About the emails - can I just save their email to some .txt file or should I connect it with aweber/other service immediately?