Without knowing exactly what's giving the problems, the best I could come up with is links. junglistic pretty much nailed it, in my opinion - logs are another set of functions, kind of like sines and cosines, that map one set of numbers to another set, using a specific set of rules, with specific properties. I think that the most useful stuff in working with logs is learning the definition of the log and it's inverse relationship to the exponential function. Hope these help.
http://mathworld.wolfram.com/Logarithm.html
http://courses.open.ac.uk/t305/maths5.htm