Photoluminescence from porous silicon was examined using synchrotron radiation as an excitation source. The tunability of the excitation source permitted a wide range of excitation energies ranging from VUV to X-rays. This permitted site selective excitation where specific core levels (i.e. Si-K, O-K, Si-2p) were probed. In high porosity samples, luminescence bands of both surface and bulk origins were observed. All experiments exhibited a common luminescence maximum typically in the orange-red region of the visible spectrum. At certain specific excitation energies particularly in the VUV region additional peaks related to sites with oxygen character were also observed. The VUV excitation luminescence spectra of the porous silicon remarkably resembled that of oxygen deficient amorphous silicon dioxide glasses.