I've been thinking about taking the battery 'jump' cables that came with it, cutting them off, and hooking a cig lighter plug up. Where I've got the pigtail run from the battery it would be real easy to hook it up and drop the cell phone in the right saddle bag to charge while I'm riding.
Course, like Jeff said, plugging it into a house charger at the end of the day would probably be easier!
I installed a Kuryakyn chrome 12V cig light style power outlet to my RKC handlebar. It has the option of attaching the fused power supply directly to the battery or to the battery pigtail. It was over $60, but great quality and looks good. I ran the power supply to the battery and at the same time installed a shielded audio cable from the bars ending at my adjustable backrest switch. Now I keep my android phone in the WS bag charged while I listen to the navigator and tunes via my headset.