I use and love aWeber for my email system.

I could hand build a great pop up window with aWeber, but it was going to be a lot of work, so I kept putting it off.

Then I tried Floating Window.  It more than doubled my sign up rate, it integrates with my aWeber account and it really is as simple as they show in this video.

There was one thing that I did not like.  I could not have it only pop up once per visit.  So to solve that, I added it only to the front page, but not the sub pages, that still use a simpleraWeber form.

If you want to save time, impress people with a great pop-up email offer and get more people to opt into your email list, I recommend Floating Window.