The Grameen Bank , and its growing family of related projects. Microfinance for the Americas. The Microfinance Network a global association of leading microfinance practitioners. Documents from past conferences are downloadable. The Rural Finance Group at The Ohio State University has been very influential in shaping thinking in the field.
Site contains links to downloadable documents.
A nice website. Includes a book length description of the program's operating practices. OneWorld links to recent news articles on Microfinance. Has several interesting publications on credit unions, guarantee funds, and onlending.