Math Medics
S.o.s. Math: Properties of Logarithms
Site provides the many properties of logarithms, including common and natural logarithms. Also gives examples and formulas for each.
University of Guelph
University of Guelph: Logarithms
Exceptional page explaining almost anything you might want to know about logarithms.
University of Saskatchewan (Canada)
University of Saskatchewan: Modelling Natural Growth
This site shows how to model exponential growth. The site walks the student through an example problem using logarithms to find the exponential growth of the theoretical world population.
University of Saskatchewan (Canada)
University of Saskatchewan: Modeling Exponential Decay Using Logarithms
Radioactive decay is a real-life example of exponential decay. This site solves an example problem by using the exponential decay equation.