You can easily get the program in source form. The main difference with using precompiled packages is that you'll have to install the required libraries by hand. The required libraries are: PyQt, PyKDE. Furthemore, having "konsole" installed is needed. konsole is usually found in the "kdebase" package. More detailed installations instructions can be found in the sources.
There are two ways to get the program in source form: the official source release and the CVS repository.
The latest source release of the OneFinger core and OneFinger applet are available here.
cvs -z3 -d:pserver:anonymous@cvs.sourceforge.net:/cvsroot/onefinger checkout onefinger
This will create a directory called onefinger in your current dir, and put the source code of the OneFinger core in it.
To download the OneFinger kicker applet:
cvs -z3 -d:pserver:anonymous@cvs.sourceforge.net:/cvsroot/onefinger checkout kicker_applet
This will create a directory called kicker_applet in your current dir, and put the source code of OneFinger kicker applet into it.
You can also browse the source code online with sourceforge: simply click here.