Veterinary technicians in Texas are credentialed by the Texas Veterinary Medical Association. They require that you have a degree in veterinary technology from a 2 year AVMA accredited veterinary technology degree program, a passing score on the Veterinary Technician National Exam and a passing score on a state jurisprudence (laws/rule/regulations) exam.
You can currently work as "vet tech" (what is more appropriately called a vet assistant) without the education in Texas, however the Texas Veterinary Medical Assoc. and the Texas Assoc. of Registered Veterinary Technicians are both interested in getting laws changed to limit the title of veterinary technician only to credentialed technicians and to possibly even license veterinary technicians in the near future. So, going ahead with an education is a good choice and a better ethical choice since you will be taking the lives of animals in your hands every day in a veterinary facility.
You can earn a degree in veterinary technology from Cedar Valley College in Lancaster. It's the closest accredited program to Dallas, has been accredited for more than 20 years and has a good reputation. They also have recently updated their facilities, so it's a state-of-the-art facility. You can find out more about their program at: http://www.dcccd.edu/Current
Students/Courses and Programs/Programs/Health/VetTech/Pages/default.aspx
A very general list of things that a veterinary technician would do would include collecting patient histories, collect biological samples (blood, urine, feces, etc), running diagnostic tests, monitoring and medicating hospitalized animals, assisting in surgery, administering and monitoring anesthesia, performing dental cleanings, providing treatment for outpatients as prescribed by the attending veterinarian, filling prescriptions, answering client questions on preventative medicine, disease processes, medications, etc, maintaining inventory, caring for surgical and medical equipment such as anesthesia machines, taking radiographs, entering medical records, etc.
Pay and benefits vary greatly based upon education, skills, experience and exactly where you work. For example, large practices in big cities or specialty practices tend to offer better pay and benefits than single vet practices. City practices tend to pay better overall then rural practices. So, anywhere from minimum wage for those who are starting as a "vet tech" with no education/training to $20/hr for very experienced, educated people.
Your state veterinary technician association (TARVT) is a great resource for getting details on schools, requirements or many other things related to becoming a veterinary technician. You should also go ahead and either shadow an RVT or take a job as a veterinary assistant in a clinic to get some first-hand experience as to what the job is really like before you enroll in college.