The iPhone 4 announcement is only hours old, but after a hands-on and  poring through tons of Apple documents on the new device, we’ve found a  bunch of new details that you probably didn’t already know from the  unveiling. Without further delay, here’s the list—and there will be  plenty more to add in the near future. Thanks to Charles Starrett for  his assistance in compiling this list.
   
  1. 802.11n, Limited. While iPhone 4 does include support for  802.11n Wi-Fi, it is limited to 2.4 GHz only, meaning that users of  Apple’s own dual-band Wi-Fi hardware may be out of luck in taking  advantage of the AirPort Extreme, AirPort Express, or Time Capsule 5GHz  802.11n functionality. 
  2. Faster Uploads + HSUPA. iPhone 4 adds support for HSUPA  cellular connectivity, also known as High-Speed Uplink Packet Access,  which increases maximum upload speeds to 5.76 Mbits/second, a  theoretically major improvement over current speeds seen on iPhone,  iPhone 3G, and iPhone 3GS models. Unfortunately, upload speeds on iPhone  3GS devices are much lower than this—U.S. users see 0.2 to 0.3  Mbit/second rates, generally—and since the HSUPA feature is not yet  supported by most cellular carriers, users won’t be able to take  advantage of the new technology. This slow speed makes multi-picture and  video sharing very sluggish whenever you’re not near a Wi-Fi network.
  3. Fingerprints and Oleophobic Coatings. The addition of glass  to the back of the iPhone 4 raises new concerns over durability and  scratchability. Apple has sought to relieve those concerns by noting  that the glass has been specially designed to resist damage, and notably  says that both the front and back glass surfaces of the device feature  an oleophobic coating. This coating will make fingerprints and smudges  easier to remove from the iPhone 4 than on the iPhone and iPhone 3G,  just like the screens of the iPhone 3GS and iPad, however, it’s worth  mentioning that the devices still attract those markings en masse: Apple  had personnel at each hands-on demo station using cleaning cloths to  wipe each iPhone down immediately after it was set back down, in  preparation for the next person’s use and photography. It’s unknown  whether the oleophobic coating will have the same tendency to display  fine scratches as before. 
   
  4. 720p Video.As with the iPad, the iPhone 4 now offers  support for 720p H.264 videos and motion JPEG video playback—a big jump  over the 640x480-capped iPhone 3GS—though MPEG-4 video is still limited  to 640x480. Consequently, videos from the iTunes Store designated as  “HD” will play on the iPhone 4, as will unconverted .AVI-format M-JPEG  HD videos made on certain cameras, including some recent Nikons, but  1280x720 MPEG-4 videos recorded by other video cameras will not work on  the iPhone 4 without transcoding.
  5. Video-Out. Apple has indicated that the iPhone 4 will be  compatible with the iPad Dock Connector to VGA Adapter, which may see  the “iPad” reference dropped from its name. This adapter is currently  the highest-resolution video output solution available for Apple’s  iDevices, but does not provide audio output, and is capped at 1024x768  resolution—modestly below the 1280x720 capabilities of the iPhone 4.
  6. The Second Video Camera’s Resolution + Accessibility. The  front-facing camera is now confirmed to be VGA (640x480) resolution,  fully sufficient for video calling purposes. It can also be accessed  from within the Camera app by tapping a “flip-around” button in the  upper right-hand corner, so that you can take pictures of yourself  without turning the iPhone.
   
  7. Those Little Dots. The white version of the iPhone 4 has a  white faceplate. While it’s not entirely obvious from Apple’s  photography, the white version has what appears to be an unusual row of  mesh-like openings directly above the handset speaker. They’re not  actually openings, but provide the proximity and ambient light sensors  with the ability to see through the glass.
  8. Keyboards. Though this feature is really an addition to iOS  4 rather than the iPhone 4 itself, the new device supports Bluetooth  keyboards, just like the iPad. This means that users frustrated by the  iPhone’s on-screen keyboard will have additional typing options.
   
  9. Making Video Calls. Apple’s video calling feature works in  two ways. First, there’s a FaceTime button prominently displayed on  iPhone 4’s in-call menu when Wi-Fi is available, replacing the “Hold”  button previously found on that screen. Second, you can make a FaceTime  call without placing a traditional call first. Use Contacts, find the  person you’d like to chat with, and tap the FaceTime button from within  their contact listing. 
  10. Accessibility. Some new Accessibility features previously  undiscussed by Apple have made their way into iPhone 4, and possibly  into other iOS devices. One we’d heard about before was Large Font,  which lets users increase the font size of text elements within Mail,  Contacts, Notes, and Messages. New is Touch Typing, which has been added  as a tool to help visually impaired users type on the keyboard, letting  the user run a finger across the keyboard to hear each letter spoken  aloud, then lift the finger to select the letter. VoiceOver has added a  new virtual controller called the Rotor, which senses the use of a  two-finger spinning gesture that simulates the turning of a dial,  changing the language VoiceOver speaks, or the way it moves through web  pages. Depending on the setting, you can move through the page by  flicking to skip from header to header, link to link, or image to image,  and “add settings to the web rotor such as lists, tables, text fields,  and buttons,” notes Apple.                         article by  By Jeremy Horwitz