First Professional Degree:
Bachelor of Architecture or Master of Architecture

Completing a five-year undergraduate course leading to the Bachelor of Architecture degree. Applicants may be required to take the SAT.
A four-year pre-professional degree, such as a BS in Architecture, BS in Architectural Studies, etc., followed by a two-year course leading to the Master of Architecture. The latter two years may require the GRE and a portfolio for entrance.
After obtaining a Bachelor's degree in a non-architecture subject, completing a three-to-four year Master of Architecture degree. May require the GRE.

The Bachelor of Architecture and the Master of Architecture programs must be accredited by the National Architectural Accrediting Board (NAAB). There are over 150 such programs in 111 schools. The four-year pre-professional degrees, however, do not have to be accredited by the NAAB for either entrance to the Master of Architecture program or for licensing purposes.

Licensure

Most states require that the first professional degree must be followed by three years of an internship, after which the candidate must take the four-day comprehensive Architect Registration Examination. Each state may have slightly different requirements, and it is necessary to check with the state registration board in which one wishes to be licenses.

Post-Professional Study

Those who already have a professional degree in architecture may wish to obtain a Master's or doctoral degree in a specialized area such as design theory, solar design, etc. These programs are not accredited by NAAB or CACB. GRE and a portfolio are usually required.

Non-Professional Graduate Architecture Programs

There are some graduate degrees in architecture which do not require a first professional degree for entry, They are intended for people who wish to pursue non-professional graduate work in architecture. An example is the Masters of Arts in Architectural Studies (M.A. Arch.).

References:
Guide to Architecture Schools, 6th ed. 1998, Washington, DC, Association of Collegiate Schools of Architecture. A comprehensive reference, but only published every five years. "Accredited Programs in Architecture". Washington, DC, National Architectural Accrediting Board, 2001. Available on web site: http://www.naab.org