Apple has refuted early assertions that GPS-based driving directions on the iPhone 3G are impossible because of the GPS transponders' size, and left the door to copy/paste functionality open. Per an ExtremeTech interview with Greg Joswiak, Apple's Vice President of Marketing:
Copy/Paste: "Apple has a priority list of features, and they got as far as they could down that list with this model." -- apparently copy/paste was not high enough on the priority list.
GPS driving directions: The iPhone's GPS is "just like the GPS in other phones, many of which do provide driving directions," but there are some "complicated issues" preventing driving directions at present "It will evolve. I think our developers will amaze us," Joswiak said.