This is a pretty good comparison video, barring some audio fluctuations. We already know about most of the changes in the new Vita:
•it's lighter and thinner than the PCH 1000
•an extra hour of battery life, probably oweing to the change in screen type
•it now has an LCD instead of an OLED screen
•it comes with 1GB inbuilt storage
•it has a micro USB charging port.
A few things I didn't know:
•the accessory port is gone, there is only a game slot at the top which I assume means Sony won't be releasing any peripherals to take advantage of that accessory port.
•The 1GB inbuilt storage apparently disappears when you install a Vita memory card. That is to say you can no longer access the onboard memory if you have a card installed.
•The battery is user-replaceable