Today is the first time I've ever opened my own pomegranate...GASP! What kind of raw-foodist am I anyway?
There was an instruction manual on how to open/eat one at the store, and I couldn't resist (my mom was raving just recently about the awesome pomegranates she's been eating).
So, here's basically what they said (with my own photos to help us along):

• cut the 2 ends off so the fruit lays flat on the cutting board (see photo)
• cut the fruit into sections (see photo)
• submerge in a bowl of water (see photo)
• remove skin and white pith (much of which floats to the surface of the water as the seeds sink) by picking and rolling between your fingers (see photo)
• discard/compost pith (see photo)
• strain pomegranate seeds and enjoy! (see photo)