Most cameras have a function where you can decrease or increase the brightness of the flash. I, too, had that problem on the built-in flash on the Nikon D40, so I toned it down to -1 power, which illuminated the subject but didn't wash out. Also, if you're shooting an external flash, try toning the ISO settings on the flash to a lower number or decreasing the power. Also, angling the flash away from the subject slightly helps a great deal.