If you're confused about the changing landscape of media outlets in the arts, you're not alone. Drew McManus of Adaptistration is currently writing a series entitled How To Connect With New Media. Part 1 attempts to define what new media is and how to identify new media sources (of which CPB is one). This series will be required reading for anyone in the arts that is looking to publicize artists, events, or products and wondering how it can be properly done.
Although Drew`s series is probably the first of its kind in the arts, there are already guides on how to approach bloggers, the most comprehensive being Darren Rowse`s article on ProBlogger entitled How to Pitch to Bloggers - 21 Tips.