I got the cable for my Iphone at Best Buy. Not sure if your samsung takes the same type cable, but it's just a standard headphone type plug on both ends for mine. Plugs right into the aux port in the stereo. Just got a Kuryakyn mount that goes on the handlebars and my phone clips right on that. Makes it easy to scroll through songs while riding, or make videos of the ride too. Very handy little device.
Here's a link for the inter-web. But I'm betting Best Buy or Radio Shack will have them on the shelf
NoiseHush AS12 3.5mm Auxiliary Cable - Smartphone Audio Adapters - Mobile Nations Mobile Accessories