The powerlet folks made a cable for me, goes directly from the iphone to the sae battery tender connecter. It has a inline fuse and the power reducer (dont remember the fancy word they used) to make sure the iphone got the correct amount of juice. Its 24" long (they could have made any length). I plug my iphone in and drop it in the saddle bag when i need a charge. Has worked great for the past several months. Cost was about 45 i believe with shipping.

If you have an iPod/iPhone/Android data/charging cable(comes with all phones), you can get an adapter at www.americancrossroaders.com for about $30.00