Silvery - 3:30 pm on May 13, 2008 (gmt 0)

I've called for something like you're describing previously -- a sort of open business profile which could be used by local search engines similar to how Sitemaps are used. So far, the big companies haven't come together to accomplish this, though.

What you can do is optimize all the common elements of your business's profile in order to serve you best in all directories/search engines, and then update your data in all the big ones individually, using that info.

Some common elements include:
Biz Name
Address
Phone
Email
URL
Tagline or Description
Keywords
Business Categories
Amenities
Products
Brands
Services
Hours of Operation
Menus
.... etc.