cSurvey is currently available in the compiled version, solely as a compressed zip archive.
In a system with all requirements it does not require any setup and can be run directly once unzipped (even on a USB flash drive or on a removable media).
If you have found an error or contacted the author for any problems, you can download the latest build of the program from this page.
Here you can find cSurvey source code.
It’s also available for download a draft of the manual includes a brief tutorial (available only in Italian).
Note: This document is outdated but is the only one actually available.
The actual version has been updated at 07-15-2013.
Might not reflect the most recent changes.
At this link you could download some examples useful to start learning cSurvey.
At this page you can see the details of the license.