Kevin Drum did an analysis for the Washington Monthly, of the deceptions and misstatements by Bush and Kerry. His conclusion: The degree of deception employed by Bush exceeds that of Kerry.
He also reports that an internal ABC News memo by Political Director Mark Halpern was intended to encourage reporting of deceptions, rather than creating balance where none actually exists.
(Note that the above-linked page has gotten really big because of all the comments by readers. Dial-up readers beware — download could take a while.)