In short, psbind is a smarter psnup.

psbind examines the margins in a PostScript document and rearranges the pages to fit them onto paper efficiently. It outputs a transformed PostScript document.

Because psbind detects the margins in its input automatically, it is particularly useful on documents with large or unbalanced margins. For example, many PostScript documents are laid out for paper sizes smaller than A4 or Letter. psbind can place two such pages onto one output page, often without shrinking the text. It is also useful for printing documents formatted for A4 paper on Letter stock, or vice versa.

The latest version of psbind is dated 2009-03-15. It is available from the Comprehensive Perl Archive Network and as a Debian GNU/Linux package. Documentation is embedded within the program; you can read it with the command “psbind --manual”.