It is 6% for the Macbooks.
$1221 for 2.0, $1503 for 2.4
And you are able to use the EPP discount in the Apple stores. I don't know what you have to show exactly though. My boyfriend works for Comcast but it didn't say so on his ID for some reason, so he brought his benefits card or something. It had the company name and his name, I think.
Also, I was able to use both my student discount (2.4 was $5 bucks cheaper with it) and the EPP discount, since the Mighty Mouse isn't discounted with the student discount. I don't know if you're a student, but if you are, you should check with both discounts to see how much you can save.