I was just going over my documents and forms for the interview again, and then I found this on an information sheet I got with my I-134:

To substantiate the information regarding income and resources the sponsor should attach two or more of the following items to the affidavit:
1. Notarized copies of his or her latest federal income tax return;

Now, I didn't see that until now and my interview is next week, and there's no time to have a notarized copy sent to me... did anyone hear about this before, or did anyone have their tax returns notarized?

You don't need notarized tax returns but they do need to be complete with W2's and 1099's if applicable. Alternatively, you could call the IRS and have them fax tax transcripts. Transcripts are actually preferred.

Thank you so much for your fast reply! I should have everything then.. I'm just getting a little nervous because it's so soon and I want to be well prepared. : )

The only thing I ever submitte that was notarized was affidavit of support for the K-1 and AOS