I do not use excel much, but go to http://realestate-calc.com
You can do this yourself very easily there. If you want to see how the math works: Principal (amount you borrow) X rate (8%) X time (30/360). This will give you the amount of interest due for the first month. Subtract this amount from the payment amount you obtained from the above site to get the amount of principal paid on the first payment. Subtract this amount from your original principal balance. You now know how much you owe on the note after making the first payment. Take the new principal balance, and put it through the formula again for your 2nd months payment and so on......358 left to go!