electrical question

i know a lot of guys ride listening ipods, mp3 players, etc. i have a minidisc player that i pretty much never use. i've never listened to anything while i ride but i've been thinking a lot about doing a little audio customizing on my bike. i want to take the speakers outta some good headphones and put them under the padding in my helmet and run the cord down so it exits in the middle right below my mouth (permanently). then put my player somewhere inside the bike, waterproofed somehow, with my shuffle mounted by my left handgrip. then i'll have the cord just long enough to reach the jack sticking outta my helmet. anyone think this is stupid, cool, whatever? the other question i have is how can i make my player, which runs off a rechargable battery, be powered by my bike battery. is it possible, and if so how could i do it? thanks.