In general, it is not allowed to work in the United States on a student visa. Although you can get jobs within the university as a teaching assistant or assistant librarian, you will not have the opportunity to acquire additional funds from this type of work as they are highly competitive, pay very little and you can not choose them for the first year of studies.
However, just after finishing your studies in the United States is allowed to complete an internship job known as "practical training" in a local company for a year, for which you must obtain a work permit. Once this period, you could opt for an H-1B visa, or temporary employment, if the employer gets sponsorship.
If you work without appropriate authorization can be violating U.S. law and you may be required to leave the country immediately.
To get an idea of the jobs available, visit the pages of the major newspapers in the cities where they are located American universities.
