The Census Bureau started release of Summary File 1 (SF1) data from June 13, 2001 on a state-by-state basis.
SF1 contains the 100-percent data, which is the information compiled from
the  questions asked of all people and about every housing unit. Most of the SF1  data is reported at the Census Block level. Since the Transportation  Analysis  Zones defined in TIGER/Line 2000 are aggregations of Census Blocks,  transportation planning agencies can assemble SF1 data for their TAZs.
Attached is a note on SF1 data and a process to convert SF1 data to your TAZs.
Note to SAS and SPSS users: A code to automate the data transfer is posted  at:
http://www.sdcbidc.iupui.edu/Profiles/profiles.html
Thank you
Nanda Srinivasan