I would not exercise with my S3. It is way to big and expensive to risk damage from rain, falls, and sweat. The S3 arm bands are huge. Kinda looks like you have a tablet strapped to your arm. Go out and buy a small cheap mp3 player for 15 dollars. You will be happy you did.
Also, never listen to music when running on / near the street, bike paths, etc. Your life is more important than a playlist.
I run during work hours and have no choice but to keep my phone on me. Plus, RunKeeper is an amazing companion, being able to track stats keeps me motivated and running more.