Hey Brian,
There are lots of good guides in the Interweb for choosing blades. One good thing, is that for the most part, you can even read an article on explaining table saw blade types and apply the same logic to your circular saw blades, chop saw blades etc.
Understanding stuff like why a different number of teeth, what's kerf mean, ripping vs. cross cuts, etc. are pretty universal across any round blade.
I mention this because I'm guessing you may have found difficulty trying to web research circular saw blades in particular, as many Average Joe's never find the need to swap away from a good combo blade on a circular saw. People with miter saws and table saws tend to change blades more often to suit their purpose so you may have better luck searching under the guise of say table saw blades and then applying much of the same logic. That is if you are interested in more info now that the original dilemma has passed..
