PHP generates output, which you can capture and paste it into a text document.
The text document can be loaded using a program such as notepad and then printed from the File menu bar at the top.
You could go to: http://us2.php.net/fopen and use fopen to open a file handle to LPT1 and print. I don't think it will work though. Of course, if you do get that to work, google for the PostScript language and there ya go.