for the most part, if you go to College, the discount applies to students... but for K-12 schools, students dont get a discount... only faculty
did you know if you want to buy at an apple retail store, with an educational discount, you can just ask one of your nice teachers to write up a small paper saying its "OK" for you to buy an Apple Computer with their discount. thats what my dad did with my mom (she is the PTA President for my brothers school, and that qualify's for EDU discount).
funny thing is too, when I bought my Powerbook, I told them the college I went too, and he punched it up, and didnt ask for ID or anything. I did pull my ID out though but he just kinda 'waved' it away saying 'its ok'... i was like... ook
I've heard a couple odd-ball stories of Apple actually calling the school, then calling you.... but I dont know if thats true or not, seems like Apple just uses the honor system...