Can anyone tell me why this competition between US teams is called "World" Series, when it is only one country involved?. Shouldn't it be called just "National Series".

Try this link:

http://roadsidephotos.sabr.org/baseball/name.htm

Toronto is in the US??

Are you serious with this question?. It is in North America, Yeah! but fortunally is not part of the USNA (United States of North America).

Toronto is in the US????

Nope its Canada :)