Dawn,
I've used ReachForce, which provides similar services, and been happy with the results. They have several tiers of service, including a data cleanse product to fix your existing database, smart forms to append multiple fields in real time, and an ongoing program to clean once and keep data updated.
As with Rafael, I don't work for ReachForce.
I think you can connect with both companies via Marketo LaunchPoint: launchpoint.marketo.com