Installing the picturing-programs teachpack

The textbook uses an optional library named (imaginatively enough) "picturing-programs". Since there have recently been a bunch of version changes beyond my control, here's my advice on how to get things working:

If you're using the Summer 2011 or later version of the book (printed or online), with DrRacket version 5.0.99.6 or higher,
you don't need to install anything, as the library is included with DrRacket, and can be invoked by saying
(require picturing-programs)
You may occasionally find a reference in the book or the worked exercises to
(require installed-teachpacks/picturing-programs)
Ignore this.
If you're using the August 2010 printed version of the book with DrRacket version 5.0.99.6 or higher,
you don't need to install anything, as the library is included with DrRacket, and can be invoked by saying
(require picturing-programs)
However, the printed book still says
(require installed-teachpacks/picturing-programs)
If you're using the August 2010 printed version of the book with DrRacket version 5.0.0.1 through 5.0.2,
Don't. Download an up-to-date copy of DrRacket, and ideally of the book too.
If you're using the May 2010 (or earlier) pre-release draft of the book,
Don't. Download up-to-date copies of the textbook and DrRacket.