Hi Dave,
As Matt and Robert have said, it's a Moro punal or gunong. I'm far from an expert, but do collect them. Federico has some info on his web page.
http://home.earthlink.net/~federicom...roweapons.html
Others are much more knowledgeable, but I'd guess post WWII. It's a nice example. Here are some other types. More pics at:
http://smg.photobucket.com/albums/v1...Public/Gunong/
Steve Ferguson