I've search countless Subaru forums for a quick and effective way for this and it wasn't until I found a post on a totally unrelated forum, that I found this information.

Credit goes to Lanichol over on rotaryforum: http://www.rotaryforum.com/forum/showthread.php?t=13062


Here is how to identify the Phase I vs Phase II Subaru engines 95% of the time as there were a small number of phase 2 blocks with some phase 1 internals.

On the passenger side of the engine block. Look down at the block just behind where the power steering pump use to be located. You will see the words "Japan". Just in front of that will be either 1 ridge or 2 ridges (approx. 3-4 inches long) If there is one ridge, it's a phase 2 block, if there are two ridges it's a phase 1 block.

SOHC vs DOHC id
A way to tell for sure is by looking at the timing belt cover in front of the heads, if there is one pully (nice semi-circular end to the cover) it is a SOHC "standard overhead cam", if there is two (a sort of square end with two rounded corners), it is a DOHC.
There is also a hidden VIN on the engine block itself. I found this while i was cleaning up one of my blocks. If youve ever bought a motor outside of the car, you can verify the year of the motor and approximate mileage of the engine by running the carfax. The hudden VIN is on the passenger side (right with front of engine facing you) of the block near where the engine bolts to the transmission.

This is my EJ222 Phase 2 markings:

This is my EJ25 Phase 1 Motor from a 97 Outback:

This is the hidden VIN on my EJ222 not cleaned up:

Here is the hidden VIN on my 97 EJ25 when it is cleaned up: