Image from iFixit
The gadget mechanics at iFixit have already taken apart the Droid 2. It turns out that the device hasn't changed much from the original Droid when looking at the inside, and they say that it's actually hard to tell which is which when the handset it cracked open.
They did point out some interesting things. For one, the Droid 2's battery is identical to what comes in the Droid, but Motorola's claim is that the battery will provide 575 minutes of usage time in this phone, compared to the 385 minutes of the other phone. That's a good deal less power consumption with this phone. It also seems that Motorola labeled the area where the battery can be removed, whereas the iPhone's battery is labeled with an "Authorized Service Provider Only."