From the journal Evolution: Education and Outreach is an article by Adam M. Goldstein about blogs that discuss evolution [PDF]. The abstract:

A weblog (“blog”) is an publication on the WorldWideWeb in which brief entries are displayed in date order, much like a diary or journal. I describe the general characteristics of blogs, contrasting blogs with other of WWW formats for self-publishing. I describe four categories for blogs about evolutionary biology: “professional,” “amateur,” “apostolic,” and “imaginative.” I also discuss blog networks. I identify paradigms of each category. Throughout, I aim to illuminate blogs about evolutionary biology from the point of view of a user looking for information about the topic. I conclude that blogs are not the best type of source for systematic and authoritative information about evolution, and that they are best used by the information-seeker as a way of identifying what issues are of interest in the community of evolutionists and for generating research leads or fresh insights on one’s own work.

Goldstein lists/describes many evolution blogs and separates them in the following categories: professional, instructive amateur, organization and project, apostolic, imaginative, and networks. Included are some blogs with which I am familiar (Pharyngula, The Loom, The Flying Trilobite, the Beagle Project blog), and others not so much. But the list is missing The Dispersal of Darwin! Oh well.