The karel software is freely available as described below.
This tutorial uses the first two full chapters of the Karel++ programming text ( Karel++, by J. Bergin, M. Stehlik, J. Roberts, R. Pattis available from Wiley Publishers, ISBN 0-47-13809-6), a terse section on the rest of Karel programming that is meant to be augmented with class lecture, and a section on using the Karel++ software.
Getting The Karel++ Software
The Karel++ software is usually in a file called Karelpp.exe in a folder called karelwin. You can download it here. This is a 392KB Windows Zip file (so it fits on a floppy) of the karelwin folder. You will need to unzip it to use it. The folder containes both the karelpp.exe Karel++ application (334KB) and some sample Karel programs. A Macintosh version is here , it is compressed with Stuffit.