First the NEC is yes for the United States.
You cannot you or should I say, you should not use this code book for the Exam you will write for certification in Ontario.
Although they have become very simular over the years as far as rules go, the layout of the book is very different and may very well confuse you. All the rules and tables have different numbers.
The Ontario exam is based on the Canadian Electrical Code book, Note:not the Ontario Version.
For training material there are or used to be books which you could buy from a Community College such as Humber or George Brown. This is the stuff they use for the Night School Courses "Electricians Pre-Exam course".
I'm not sure if there is a local college that offers such a course, but if they do it would be a really good idea to take it before writing exam.
Good Luck and I hope this helps.