Multiple sources have told both MacRumors and ifoAppleStore that participating retail stores will allocate 40 hours of time per week, split up among a number of employees, to manually examine Apple's mapping data in their areas and submit any necessary corrections.
However, ifoAppleStore said the effort was voluntary, not mandatory, so its unclear how this will work. Apple stores could have employees manually cross-examine Google and Apple Maps data (although Google is not always right, either), or they could examine locations nearly in person, in which case you'd expect them to be compensated for transportation costs.
Apple famously decided to dump Google Maps from its recently launched iOS 6, despite having over a year left on its licensing agreement for the product. While the company may have felt that its home-built Maps product was ready for prime-time (and it certainly advertised it that way at WWDC earlier this year), the results and feedback from end users shows that the iOS 6 Maps app was nowhere near release quality.
The app, which does work OK for some, but not so well for others, has led people to the wrong end of the street, displayed airports where they don't belong, and has even been called "dangerous" by the Irish Minister of Justice. It's been turned into a meme, things have become so bad.