Originally posted by Academic:
It stands for Personal Ticket Office, AC's proprietary booking system. You can access it through http://www.aircanada.ca/pto/home.html
When you go there it will tell you that you must have been contacted by AC in order to use it. Ignore that and register then download. I didn't have any problem as an Elite. You will need to contact PTO to have your account activated, but that is straightforward. It's not perfect, but I prefer it to ITN except where I need to see what booking classes are available.
You register here after you download the software.
http://www.aircanada.ca/pto/regis.html
and read this:
http://www.aircanada.ca/pto/guide.html#registration
Then you launch the program and use your Aeroplan number as ID. Your default password upon connecting for the first time is 'aircanada'. You will be required to change this password and replace it with your own password.
Voila... simple registration. No invitation or human contact required.