I would wait because if you file before you receive that Form 1099-MISC, then you would need to amend your return.

The IRS receives the same forms you do and would be looking for them on your return.

However, if you know the amount and want to file without that Form 1099-MISC, you could do so using the amount and the instructions below:

Your self-employment income was only from cash or personal checks or credit card payments (OR you didn't receive a Form 1099.    
Type “Schedule C” in the Search box and then select the “Jump to” link. This will take you to where you can enter any cash, personal checks or credit card payments (Form 1099-K) related to your self-employment. You may first be asked some general questions about your business. After you answer them, you’ll be taken to the Let's get income for (your line of work) screen where you can enter this income as Additional Income. It will still be counted just like a Form 1099-MISC.