I found this paper about the problems software patents would cause for schools: http://www-old.eun.org/insight-pdf/special_reports/e_learning_softpat.pdf
Most interesting regarding free software are section 3.2 on how two-thirds of schools do in-house developement, and section 3.3 on the value of free software to schools.
The whole doc is 8 pages. The arguments are in section 3 which goes from pdf page 4 to pdf page 7.
(If anyone knows other docs/arguments regarding software patents and education, please feed: http://en.swpat.org/wiki/Harms_to_education )