Bruce Ralston from the Geography Department at the University of Tennessee in Knoxville, has posted a program that will convert U.S. Census TIGER format files to Google KML format.  The program works with TIGER formats from dating from 1994 to 2006.  Currently, the program only supports the conversion of polygon based layers although there are future plans for line and point files.  Additionally, the source code and associated white paper will also be posted to the site by the end of September. 

Note: The site can only accomodate a limited number of concurrent users so if you get an error accessing the site, try again later.