Definitely need the property address to give you current taxes (2010) and information on any exemptions that may be currently applied.
You can check http://www.bcad.org/clientdb/?cid=1
(links direct to tax search on Bexar County Appraisal District). In the drop down menu, select "Property Address" and enter the "Street Number" and "Street Name" (note, they are two separate fields, if you put the entire address in one box, your search will not return anything).
This will give you current tax information.
Bexar County has been doing a lot of checkups on tax valuations lately, particularly after a home is sold. I've recently had some "off" numbers and information coming out of BCAD, so be aware that the numbers you see for 2010 taxes might change for 2011 taxes (whether it be by a new tax valuation, a tax protest, or updated data within their system).
I wrote about some of the inconsistencies recently, I left a link below.
You can also get a local RealtorÂ® to pull the MLS file which will give you information about the taxes and information about the property as well.
Hope that helps!
Matt Stigliano, RealtorÂ®
"Your all access pass to San Antonio real estate."