There's been some confusion on whether this law has been passed in Ontario or not.  Judging by the sheer number of cell phone users I see driving every day, I would've guessed it hadn't passed.  However, it has!  http://wiselaw.blogspot.com/2009/04/ontario-drivers-cell-phone-ban-passes.html
The ban takes effect this fall.  Hands-free use is still legal however (despite studies that have shown it is no less impairing).