Valknut is available in Fedora Extras, or just Fedora starting with Fedora 7.
A simple "yum install valknut" is sufficient to install it.
RPMS generated by the openSUSE build system.
Just download the files for your OS into a new directory and do "rpm -ivh *.rpm".
For i386 and PowerPC you can add to you /etc/apt/sources.list:
deb http://pulsar.unizar.es/~meskio/deb/ unstable main
And run:
# apt-get update
# apt-get install valknut
Note that they install valknut into a non-standard prefix of /usr/share/valknut, so you need to run /usr/share/valknut/bin/valknut. Also, valknut is linked statically to dclib so that you only need to install the valknut package.
Download the valknut .deb and install it with the dpkg program. See "man dpkg" for help.
The current version is only available for 10.4 or later and Intel processors.