Assistantships

[airtyme]

Hi everyone, I have a question regarding assistantships. How do they usually work? Are you awarded one with the school's letter of acceptance? I have gotten three acceptances so far, but no mention of an assistantship. I e-mailed one university about this and they said all the assistantships in my department had been given out, but that I should apply for those in other departments. I noticed that there are assistantships working in a college office and even in food service in some schools. Are these a common thing? Wouldn't I be competing with all other grad students from every area? Does anyone know what a person's chances are of getting one of these? Any help would be great!

Thanks!