Can I use my foreign passport as a form of ID to take to my biometrics appointment? (I-90)

Yes. According to USCIS, acceptable forms of ID to bring with you to your biometrics appointment are a passport/photo ID from your home country, a drivers license, a military ID, or a state issued ID. CITATION: Section 1; http://www.uscis.gov/forms/file-my-application-online-e-filing/photographs-and-fingerprints