I believe the iPhone 4 still uses the old ones although there are adapters. i use the adapter because my iPad uses old and my iPhone 5 uses new, this way i can use the same cord. you have to be careful tho bc i found an adapter on buy.com for 50 cents and it broke the first time i used it.
also buy.com is now rakuten.com (sorry i still refer to is as buy.com) and i just looked they have just the cord (no wall part) for 1.75!! hope that helps