Sorry. Once a year. You can try it online, get on the education store, and you could sneak by. Couple of my friends did it and succeed. Not saying this is a 100% success rate option, but you can try.
Actually, Yes you can.
The education discount will allow you to purchase 1 desktop and 1 notebook a year. Besides they don't have a database with the names of people who have already used their discount.
Also, when did you purchase it? I think Apple classifies a school year as July 1st - June 30th. Therefore you could buy 2 of the same category in the same week and it would be considered two different years.
Wirelessly posted (Mozilla/5.0 (iPhone; U; CPU iPhone OS 4_1 like Mac OS X; en-us) AppleWebKit/532.9 (KHTML, like Gecko) Version/4.0.5 Mobile/8B117 Safari/6531.22.7)
Microcenter matches educational discount. ($50 off) and MacMall has them for $965, and you pay no tax or shipping.