Apple has filed for a map-based app that looks a tad like Latitude. Of course, nothing concrete except for filing the patent. However, you can understand why they rejected Google Latitude app when you see this diagram.
It does look a little bit like Latitude except that it has “Apple Map”. In another patent digram, it shows GPS satellite (I think), Telephone towers and a phone. This should be how the location of the phone is determined.
Nothing new here. Although Apple has always never fail to wow the world with their clean and nice apps.