This is one of the many lacking iPhone features that I've taken for granted in other basic cell phones for years. Ironically, the iPhone's weakest part is the phone.
Rogers will put through a call that has been dialed without the "1", but only after listening to a lengthy message that encourages you to program all of your phone numbers with the "1".
Sure, you can prepend a "1" before all phone numbers in your address book, however, that will cause problems if you share your address book with your computer and use an autodialer on your computer, because most land lines won't tolerate the "1" before a local number.