Eisenman, Sara. Building Design Portfolios: Innovative Concepts for Presenting Your Work. Gloucester, MA: Rockport, 2008.
Lupton, Ellen. Design It Yourself. A guide to assembling your own book.
MarjanovicÌ, Igor, Katerina RuÌedi, and Lesley Naa Norle. Lokko. The Portfolio: An Architecture Student's Handbook. Amsterdam: Architectural, 2003.
Undergraduate Portfolio Workshop presented by the University of Michigan's Taubman College for Architecture and Urban Planning. A resource for an undergraduate admissions portfolio.
This online publishing services listed above all have examples of architectural portfolios. Use the Search tools to see the examples.
Many schools of architecture post student work on their websites. They are not necessarily formatted for portfolios, but will give you some idea of the work produced at those schools. Below are a few links for some schools.