These packages are built for Debian sid (the current "unstable" release). They probably won't work on potato ("stable") systems because of dependency problems, such as glibc-2.2. They should work on woody ("testing").
Unless otherwise specified, the Debian Project has no responsibility for these packages, although the maintainer is a Debian developer. Use at your own risk. All queries should be addressed to the maintainer, Colin Watson (email@example.com).
Here is my public GnuPG key.
APT lines for /etc/apt/sources.list:
deb http://www.chiark.greenend.org.uk/~cjwatson/debian unstable main deb-src http://www.chiark.greenend.org.uk/~cjwatson/debian unstable main
If a package used to be here and isn't any more, please check the Debian archive. It should be there instead.