[sierrap615]

if you use just a small amount of current, a 3 pin linear voltage regulator from Radioshack may do the trick. but be warn, they waste a lot of energy by heat.

you can also buy DC to DC converters, where i'm not sure(Radio shack?)

another option is to find a power adaptier like for a cell phone or CD player that puts out 5volts and wire it to work. 5 volts isn't that common though. the closest you may find is 4.5V or 6.0V

lastly, if you know the resistance of the 5V circuit, you can do a little math and find a resistor to use in a voltage divider circuit (i think thats what its called)

if it was me, i would use a combonation of a resistior to knock down the voltage, then a voltage regulator, and a capatior to clean it up a little.