1) Poke around on the school's website. I don't know of any school that doesn't list their clinical rotation sites somewhere on their website.
2) Use the search function. This has been discussed quite a bit, and I seem to recall several places where the rotation sites have been listed by students at the various schools. As a general rule, most schools have at least some spots locally available and some you would move away for. 3rd year rotations are generally arranged for you, while 4th year you arrange yourself at several schools. This self-arranging in 4th year has benefits and disadvantages. Poke around for more information.