To compile a freetz kernel you have to download freetz from
http://trac.freetz.org/wiki/Download
You need a running linux such as OpenSuse with the following packages installed:
Untar the freetz package (e.g. freetz-1.1.2.tar.bz2) by running
bunzip freetz-1.1.2.tar.bz2
and then
tar -xvf freetz-1.1.2.tar
Change to the directory where you´ve unpacked the file. Then run
make menuconfig
and selected the required modules. Afterwards you have to run
make
and you´ll get a compiled kernel-image within the
~/freetz-1.1.2/image/
folder.
To compile again clean the source before:
make distclean make config-clean-deps