How to generate a booklet from a PDF file

Using ConTeXt (taken from the imposition explanation):

\definepapersize	[filius][width=136mm, height=232mm]
\setuppapersize		[filius][A4,landscape]
\setuparranging		[2UP,doublesided]
\setuplayout [backspace=0pt,
    topspace=0pt,
       width=middle,
      height=middle,
    location=middle,
      header=0pt,
      footer=0pt,
      grid=no, marking=off]
\starttext
\insertpages
  [document.pdf][width=0pt]
\stoptext

You have to replace the document.pdf with the real file name and filius with the original paper size.