hub
the only way to use a shuffle with an imac g3 is to use a usb hub of some sort. i have tested this on a friend's machine, and it LOOKS like the shuffle fis in, but in all actuality it doesn't. a ten dollar usb hub from any vendor solves this problem (be sure to buy a powered one) or you could wait for apple to release the shuffle dock and actually ship it, but who wants to do that?!