Dear All,
I can tell you that getting the work permit for Spain is a pain in the neck.
It is true that law in Spain says you cannot get a full time job with a student visa. However, you can get a job in Spain, as long as it does not interfere with your classes.
I work with students that get student visas for Spain. The Student Residency card cant take up to three months from the moment you arrive from outside Spain with your student visa. Then, once you have the Student Residency card, if you have a job offer, you can get a permit to work. It is a lenghthy process, as you have to spend time collecting several papers.
There is a page that explains it all, but it is in Spanish:
http://www.mir.es/extranje/reggral/estudia2.htm#auto. In any case, if you have the Student Visa and Residency card and you have a job offer, you should be able to work, provided you follow all the bureauCRAZY in Spain!
Good luck with the process!