Source
Linux/Mac OS X/BSDs: ./configure [--help]; make; make install (as root)
Binaries
Mac OS X (MacPorts): port install pHash
Windows: VC2008 project files available on download page.
Zauner, Christoph: Implementation and Benchmarking of Perceptual Image Hash Functions. Master's thesis, Upper Austria University of Applied Sciences, Hagenberg Campus, 2010.