AC will likely send an e-mail in December asking you to choose your 2008 rewards. Last year I filled the information in promptly and got my "new" package by mid-January.

If you don't have it before you leave, you'll have to rely on the kindness of the lounge attendants. These will help your cause:
- your boarding pass should show you as *G or E
- print out a copy of your Aeroplan statement just before leaving that shows you as Elite.