Actually MadcatNU and Pimpzilla were dead on. 85 allowed in total, no more than 25 per year. See the quoted text below from the NCAA official site.
http://www2.ncaa.org/portal/academics_and_..._penalties.html
"Football Bowl Subdivision Football
In Football Bowl Subdivision football, teams may provide scholarships to not more than 85 student-athletes, with up to 25 scholarships awarded to incoming student-athletes (e.g., freshmen, transfers, first-time aid recipients). For Football Bowl Subdivision teams subject to immediate scholarship penalties, the first three penalized scholarships will be charged against both the initial-counter and overall team-counter limits, with remaining penalties (if applicable) countable against the overall team maximum."