Claim CC300: The Cambrian explosion shows all kinds of life appearing suddenly
Claim CC301: The Cambrian explosion contradicts evolutionary “tree” pattern
Brief responses in the Index to Creationist Claims in the TalkOrigins Archive.
The Fossil Record of the Cambrian “Explosion”: Resolving the Tree of Life
Article by Keith B. Miller in Perspectives on Science and Christian Faith. Excellent discussion of the Cambrian and pre-Cambrian fossil record and what we know of the organisms and how they can be considered 'transitional forms'. The idea that everything or all phyla appeared at once suddenly, fully formed, is not supported by the fossil record. The full issue in which this article appears is also available.
Video of a talk given by biologist P. Z. Myers about the Cambrian Explosion and creationists' claims about it. Starts at 2:20.
Videos by Jackson Wheat.
Video in the How Creationism Taught Me Real Science series.
Article on RationalWiki.