I installed Sablotron and the PHP module on my home brewed Linux box. I know the Sablotron processor is available for Windows and Solaris platforms to.
I'm not sure about the PHP4 Sablotron extension module on other platforms besides Linux but I believe it's possible.
I found it quite difficult to get the Sablotron module loaded by the PHP engine, but eventually got it right. The trick is to set LD_LIBRARY_PATH equal to the directory where all your PHP modules/extensions are situated.
e.g. for my installation I did the following: LD_LIBRARY_PATH = /usr/local/lib