I got an additional letter for a graduate assistantship along with my acceptance. The assistantship covers 30 credit hours of tuition (basically the first year) along with a stipend. In return, I'd have to work about 12 hours a week for the department. I'm not exactly sure if it entails TAing or working in a lab, but I'm pretty excited about the opportunity either way. I never really expected any funding when I began this process.