There is some documentation of kinematics in our online documentation: http://www.linuxcnc.org/docview/2.2/...inematics.html
To develop kinematics modules or other HAL components, you must install the "emc2-dev" and "build-essential" packages using synaptic or apt-get.
The source for several sample kinematics can be found in the source code, or viewed online. For instance, the sample kinematics "rotatekins" rotates the X and Y axes 45 degrees: http://cvs.linuxcnc.org/cvs/emc2/src...-cvsweb-markup
For kinematics modes that are all in one ".c" file, they should be installable by running "sudo comp --install whatever.c". For more about how to compile and install new components, see http://wiki.linuxcnc.org/cgi-bin/emc...ll_a_component
If you write a kinematics module that you think may be useful to others, consider contributing it on that page.
These instructions should apply equally well to the newly released emc 2.2 or the older emc 2.1.