All items have values above 255, making it easy to separate the Block IDs from the Item IDs.
The item IDs seem to correlate with item IDs from the desktop edition. This list is based on a list of all item variables in the Item class.
Caution: These lists are not up to date for MCPE 0.12.
These are entity IDs found in the getEntityTypeId methods of both the disassembled Android libminecraftpe.so and decrypted iOS minecraftpe binary files.