The precinct level voting data is available for Harris County. Better have a fast connection. It is not a database but PDF files so you have to do some keyboarding, or importing and converting to use it. My suggestion is to use the Adobe select tool on the data rows you want, save into a text file and import to Excel as space delimited.
Here is an example of what I do with the data. This is Texas House District 144 and shows Talton's percentage of the vote mapped over approximate precinct voting locations. Approximate because I don't have the few hundred dollars needed to update my mapping software and they need to be adjusted anyway for the voting locations with more than one precinct.
Note the conservative heart of his support in the white upper-middle-class subdivisions from Spencer to Crenshaw. District 144 days of being in Republican hands are numbered with the changing demographics of Harris County and the Democratic Party rebuilding from the roots.
Here is another mapping of votes project done along Richmond where I used to live. Another election graphic for the same area. Chuck Kuffner, another election geek, has also been crunching the data.
Speaking of election geeks -- for $5 you can pick up a fun little software game as a stocking stuffer. You have been chosen the political manager of a presidential candidate in March after he wins the primaries, now what do you do? Lots of fun with political ads, speeches and dirty tricks - just remember you don't need a majority of votes - hit those battleground states, concentrate on one to three broadly popular issues, set up