A very straight forward approach is to use an installed Adobe Reader or any other PDF viewer capable of printing:
Code (C#)
Process p = new Process( );
p.StartInfo = new ProcessStartInfo( )
{
CreateNoWindow = true,
Verb = "print",
FileName = path //put the correct path here
};
p.Start( );
Another way is to use a third party component, e.g. PDFView4NET