You could sign up with mailchimp. I have a paid account there but there free account allow's you to have up to 2,000 subscribers and 12,000 emails per month. Details at the below link for the free version. You will certainly be able to create forms to capture emails.
What do you want with the IP address? IP's change constantly as someone may be using a proxy IP. or subscribed to your list when they was on break at work then continue to visit your blog from there home computer which is a different IP you don't have.
All you need is first name, last name, phone number....etc