From apple's website:
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Who is Eligible To Purchase
The following education individuals are eligible to purchase through the Apple Store for Education individuals:
* Faculty or staff member of a public or private Higher Education Institution in the United States
* Student currently attending or accepted into a public or private Higher Education Institution in the United States
Qualifying purchases per academic school year (July 1 - June 30):
* Power Mac, iMac, eMac, PowerBook, or iBook - One per year
* Printers - One per year
* Displays - Two per year
* Software - Two per year
Agreement
I agree that I am a member of one of the defined groups above eligible to purchase and that the products being purchased direct from Apple Computer, Inc. are for my own personal, education, and/or research use.
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You can go here to find your school
http://store.apple.com/Catalog/US/Images/routingpage.html
It will then take you to the education store. The discount is usually about 10% for hardware. However, it will depend slightly on the product you buy. The discount can be more for software. For instance students get 10.3 for $69 instead of $129.
physicsnerd