1. Martin Heller

You can rearrange pages with the pgfpages package as well.

\documentclass[a4paper]{article}
\usepackage{lipsum}
\usepackage{pgfpages}
\pgfpagesuselayout{2 on 1}[a4paper,landscape]
\begin{document}
\lipsum[1-20]
\end{document}
2. Yes, I thought that there must be a package doing similar things, but I hadn’t found it. Now I have, thanks!

3. both the tips from the original post and from the comment are helpful and a good idea.
the original tip needed some tweaking with the width of \includegraphics (\columnwidth instead of \textwidth) and the second tip doesn’t play nice with \usepackage{hyperref}, but that’s a minor problem for printing…

4. Chris E

I was going to recommend the PDFPages package, too. It’s got a ton of options for including PDFs in documents, and printing multiples-per-page, making it flexible and very useful. Here is the opening of its documentation:

“When creating PDF documents, it is sometimes useful to insert pages of other, external PDF documents. This can be done with the \includegraphics command from the graphics package. But a simple \includegraphics{doc.pdf} normally produces ‘Overfull \hbox’ and ‘Overfull \vbox’ warnings, because the size of the inserted pages does not match the print space.
The pdfpages package makes it easy to insert pages of external PDF documents without worrying about the print space. Here are some features of the pdfpages package: Several logical pages can be arranged onto each sheet of paper and the layout can be changed individually. A lot of hypertext operations are supported, like links to the inserted pages, links to the original PDF document, threads, etc.”

5. Thomas

Another option, if you’re on Linux, is the pdfnup command line tool:
http://linux.die.net/man/1/pdfnup
This tool is part of the PDFjam bundle. It puts multiple pages in a PDF onto one page in a new PDF. Handy if you don’t have the source code, or your source isn’t LaTeX to begin with.