KTurtleThe Kturtle Handbook (PDF)
The Kturtle Handbook (HTML)
Programming Refference (PDF)
Windows Computers: Download the KDE Installer for Windows and follow these instructions. Basically you need to click next a few times until you arrive to the Package Selection window. There you have to select KTurtle from the list of programs. A few more clicks on next and the installer will download and install KTurtle.
Mac Computers: There is no installer for Mac. KDE can be installed using Macports although it looks a bit complicated. Searhing in Google I found the ACSLogo program which looks pretty similar to KTurtle. I haven't tried it (I don't have a Mac) so try it at your own risk.
Linux Computers: KTurtle comes in allmost all Linux distributions. Just search kturtle in you package manager (for example synaptics or software manager) and install it.
Web-based KTurtle: The guys from rollApp have released a web-based KTurtle. Looks good but some computers have issues typing some symbols and copy-pasting. Again, try it at your own risk.