Here ya go Jay:

§ 61.183 Eligibility requirements.
To be eligible for a flight instructor certificate or rating a person must:

(a) Be at least 18 years of age;

(b) Be able to read, speak, write, and understand the English language. If
the applicant is unable to meet one of these requirements due to medical
reasons, then the Administrator may place such operating limitations on that
applicant's flight instructor certificate as are necessary;

(c) Hold either a commercial pilot certificate or airline transport pilot
certificate with:

(1) An aircraft category and class rating that is appropriate to the flight
instructor rating sought; and

(2) An instrument rating, or privileges on that person's pilot certificate
that are appropriate to the flight instructor rating sought, if applying
for-

(i) A flight instructor certificate with an airplane category and
single-engine class rating;

(ii) A flight instructor certificate with an airplane category and
multiengine class rating;

(iii) A flight instructor certificate with a powered-lift rating; or

(iv) A flight instructor certificate with an instrument rating.



Sorry for just cutting and pasteing the FARs... hope this helps.

Jim