In late summer 2005, I bought an iBook using the education discount and was also able to get the free iPod nano on the "back to school" promotion. This was completely standard stuff at the time.... nothing unusual. As you said, and as I recall, the discount was available sometime in the late summer -- early fall. I don't recall the actual dates. You just make your education purchase on the Apple Education store (I did mine online, for instance, an iBook and an iPod) and then you mail in a rebate to get reimbursed for your iPod nano. So you originally buy the iBook and iPod and then Apple will send you a check (to pay you back) for the iPod in the mail.
I didn't do it again in 2006, so I don't know what rules were enforced in 2006.