If you don't want to devote your own internal resources (time, man-power,
equipment, etc.) you might want to consider a service that JP Morgan Chase
offers called iVault. You ship you paper off to them, they scan and index
it, and you access it over the Internet. You admin the security yourself.
Physical documents can either be returned or destroyed (via Iron
Mountain). We started on it a couple months ago and it's been working
well so far for us.