Just email:
authcodes@autodesk.com
In the body put:
Hello,
My name is NAME.
The product I have is the Autodesk Design Academy with serial number:
SN-SN.
I am requesting an authorization code for Inventor 8. The request code
is: BLAH
Thank you very much,
NAME
I just copy and past the same email with a different request number for each license i want to authorize. They'll reply within a couple hours (if it's in the middle of the day). I think that's a lot easier than having to copy down that long string off the phone
Jack