Try the ACE portal here:
http://www.cbp.gov/xp/cgov/toolbox/a.../ace_app_info/
Southern Ontario switched on or about May 24 and they are enforcing. Informal entries are exempt for the time being, but other than that I think you need ACE.
We setup our account almost a year ago. If you haven't applied by now.....well, it's kinda last minute and I don;t know what the wait times will be like but probably not good.
1(800)927-8729 is the ACE help desk. You may have to wait 30 minutes on hold but they always answer. Try calling at 02:00 or some off peak time like that.
Good luck.