Here's how to add an Email Subscription button to your Blogspot site using Feedburner:
(assuming you have a blogspot site and a Google login)
1. log in to your blogger account, this will also allow you access to feedburner
2. go to http://feedburner.com
3. where it says "Burn a Feed Right This Instant" there is a box, type your blog address in the box
4. on the next screen, enter a title for your feed: use your blog title, also choose RSS for your "feed"
5. from your Feedburner control screen, click on the title of your blog
6. you should now see the controls for your feedburner info, press the "Publicize" tab
6. click on the Email Subscriptions section
8. pick a language (like English), then scroll down to "Use as a Widget" and change it to read Blogger
9. you'll be directed back to Blogger, where you press "Add Widget"
10. you'll now be directed to the "Edit Layout" section and the "Subscribe Via Email" box should be added
11. press the Save button