Compressed prop or object referenced by a model or animation created with Poser, a 3D human modeling program; may contain either geometry data or a reference to a .OBJ files that includes geometry information.
Uncompressed Poser prop files use the .PP2 extension.
Program(s) that open ppz files
Mac / Windows: Smith Micro Poser
Information from FileInfo.com - The File Extensions Resource.
http://www.fileinfo.com/extension/ppz
