University of Saskatchewan (Canada)
University of Saskatchewan: Logarithms
The University of Saskatchewan offers a brief but quality description of logarithms with a list of rules and a number of exercises of varying difficulty.
BBC
Bbc: Higher Bitesize Maths: Logarithms
A tutorial on logarithm includes topics such as the laws of logarithms, using a calculator to evaluate, and applying logarithms to real world situations. Examples and a practice test are available.