You can get easily feedburner ID. Log on feedburner site www.feedburner.com. Sign in with your feedburner id and password or you can login with your google account too. 🙂
Then click on MY FEED. which is above right side.
Now you need to click on your blog feed which you need feedburner ID.
Then look your browser where is feedburner URL. and last you will see like “id=5888873sk8974a” it’s your feedburner ID 🙂
Now! you can put your feedburner ID. where you want. 😀