Start here:
http://www.odessachamber.com/
There is a directory listing available under the "Chamber Directory"
http://www.chamberdata.net/webforms/...spx?dbid2=txod
I did a filter for engineering companies and got two. I'd recommend calling or emailing them, explaining what your team does, the mission of FIRST, and ask if they are willing to be a sponsor. Also emphasize how you help them! Remember, your robot is a rolling advertisement that will get their name exposure to tens of thousands of engineers, scientists, contractors, and business owners. You might be able to get machining time, fabrication help, or new mentors as well!
Don't stop with those two companies, either! Speak with anyone who will answer the phone! We have been sponsored by a BBQ restaurant, realtors, and other local businesses. Often, it is better to rely on several small sponsors in the community as opposed to a few large sponsors.