There's no clear and cut definition of when a phone becomes a smart phone. Usually when a phone can do a lot of tasks for which you would need to find a computer for, then you can say its an edge over a normal phone, i.e., a
smartphone.
And iPads and iPods are TOTALLY different stuffs.
iPad is like a Big cousin of Smart phones, but Smaller than a netbook. And the most perfect thing it can do is to replicate an ebook reader, since its the size of a small book.
But iPod is just a Music Player, like a modern version of Walkmans....
Hope I am clear!