Excellent site as entry point into an explanation with illustrations.
What Is Forensic Serology?
Online article from eHow.com
Article from Forensic-Medicine.info
Forensic serology - Blood
Slideshare presentation. Check accuracy of information against a ferified source
Blood may be gross, sticky and smelly, but it one of the best methods of solving crimes, where there are no suspects, but there is blood reminisce on a surface.
TV Report about the science of Blood Spatter Analysis. The CSA in the story, Daniel Holstein, is the Real Life basis for the "CSI: Crime Scene Investigation" character Gil Grissom.