This is a nice and simple introduction to microfinance which features microcredit, as explained in the video itself.

You could explore this web site which is an example of a charity organisation seeking to facilitate microfinance. There is a useful video on the home page.

Opportunity International

Similarly, this website gives details of microcredit in practice:

Microcredit on Caritas.ch

The Grameen Bank, founded in Bangladesh by Muhammad Yunas, is often cited as the main pioneer in the field of microfinance. This short video features Yunas and explains the concepts:

This video gives an example of apparent success:

WorldBank provides an example from Mauritania: