We had to amend our return because of a mortgage statement that we received late. I have done the work, printed it and now am wondering what all I need to mail in.

You will mail your amended return, form 1040X and you will attach copies of any forms or schedules affected by the changes made on the amended return. If you owe any tax based on the changes reported on the amended return, you will also send your payment with your amended return.

Please see the following TurboTax FAQ for more information:

Click here to read about how to file an amended return 

When you say attach schedules or forms that changed, these are part of the return, you are not meaning to attach for example, the 1099-I?

If I were mailing my amended return in, I would send a copy of the original return, the amended return, and a copy of any forms that you used to amend the return (the mortgage statement).  If you know there are other forms that were affected, you would send those as well.