I recently posted a brief article about the Department of Revenue's
Property Tax Informational Bulletin (PTO 07-18) on Find GIS.

http://www.findgis.com/index.php?option=com_content&task=view&id=2439...

Also, just so you know and as stated in PTO-07-18: "The assessment
roll data the Department will make available online will not be the
most current data the property appraiser has in his or her possession,
but will be data the Department used to make determinations under
oversight statutes. The GIS data, including parcel maps, will be made
available as they are provided to the Department by the counties per
Program Bulletin PTA-06-00"

Per PTA-06-00, concerning the GIS data: "maps available from the
Department are typically received by us no earlier than the end of
January each year and generally represent conditions some time before
that date.  Maps are processed and available in July or August of the
year in which they are received."