Maps Offline is a iPhone 1.X Application, which makes it possible to use Maps.app offline.
With Maps Offline, you can store your map caches offline, save routes and even search for streets offline.
Note that Maps Offline is only avaible for iPhones running Firmware 1.X.
You can find Maps Offline under the Utilities repository.
For more information, visit mapsoffline.nambrot.com