The last release of Jackfield is available for download. However, don’t download it; the release version is way out of date. Use Subversion to check out the latest code, as below.
No proper documentation here yet. See the weblog post at http://www.kryogenix.org/days/2006/07/07/a-few-notes-on-installing-jackfield for more. Please be aware that Jackfield is not stable yet! It doesn’t run all widgets; a lot of widgets have some problem or another that stops them working.
The tip-top latest Jackfield is available from Subversion. You’ll have to contact me directly to send patches. The SVN repository is at http://svn.kryogenix.org/svn/jackfield/trunk. Remember that Jackfield is not stable yet and may change daily until it is. If you don’t know how to check this out of Subversion then you probably shouldn’t be using Jackfield yet; it’s not ready and is for people to hack on, not for end-users yet (sorry!)