As above, you have the choice of thesis, project, or coursework only. If you accept a TA, RA or fellowship you are not permitted to be employed elsewhere while in graduate school unless your advisor approves it. Your chances of getting a TA, RA, Scholarship or TS as of this writing are very good. In the winter of 1995, the Dean of Engineering offered a TA to every senior from UT graduating with a 3.0 gps or higher and who applied by January 1st because UT wants to substantially increase the graduate enrollment of the UT Bachelor of Science graduates. These are usually limited in number.
Fellowships are very competitive across the university.
In addition, several scholarships are provided from various corporations. You will want to visit the Graduate School Office or the Financial Aid Office for more information on financial aid. TS's have been awarded to students who have not met the 3.0 gpa requirement and who want a chance to prove themselves in graduate school. If they perform well they may be upgraded to TA depending on supply and demand. People who have done this have found it difficult to devote the necessary time and effort after their daily work requirements, and they usually were not able to have the personal and continuous interaction with the faculty that differentiates the masters program from the bachelors program.