I've found that a standard microUSB cable from a e.g. cell phone charger will charge the Nook Color, as long as you keep it with the wifi and screen off, and you are willing to leave it like that for 12 hours or so. But the real charger and cable are the only way to charge it quickly. They have an extra row of pins on the opposite side from the USB contacts and that is used to push much more power than the standard USB connection does.
Clicking the mark as good answer button helps us highlight the best answers.