git clone git://gitorious.org/koha/mainline.git koha
OR
git clone http://git.gitorious.org/koha/mainline.git

Then
git -r branch
Will show you the remote branches,
git checkout origin/package

Gets you the package branch, then you run
fakeroot dpkg-buildpackage -b -tc -us -uc

If you want to make any changes, and build a new package with a higher patch number, run
dch -i
Then commit the debian/changelog file and rebuild your package.

Any patches gratefully accepted, once I have it fully working with debconf and the preinst, postinst, postrm scripts all going I will submit patches to patches@koha.org.

Oh, and Marc from Biblibre informed me I forgot to tell people how they can get my public key. You can get it from biglumber.com
Or simply by running
gpg --keyserver subkeys.pgp.net --recv-key 557F7779

UPDATE

I have removed the packages as people were trying to use them for purposes other than just testing.

So now we can do this, add a line to our sources.list
deb http://apt.workbuffer.org/ unstable main

run apt-get update
Then

chris@ubuntu:~/git/koha.git$ sudo apt-get install cpan-libbundle-kohasupport-perl
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following extra packages will be installed:
cpan-libalgorithm-checkdigits-perl cpan-libansicolor-perl cpan-libbiblio-endnotestyle-perl cpan-libcgi-perl
cpan-libclass-adapter-perl cpan-libconstant-perl cpan-libdata-dumper-perl cpan-libdigest-md5-perl
cpan-libexporter-perl cpan-libgetopt-long-perl cpan-libhtml-template-pro-perl cpan-liblocale-codes-perl
cpan-libmime-base64-perl cpan-libmodule-pluggable-perl cpan-libparams-util-perl cpan-libperl-ldap-perl
cpan-libpod-parser-perl cpan-libscalar-list-utils-perl cpan-libsms-send-perl cpan-libtest-manifest-perl
cpan-libtest-simple-perl cpan-libtext-csv-perl cpan-libtext-csv-xs-perl cpan-libtext-tabs-wrap-perl
cpan-libtime-hires-perl cpan-libunicode-normalize-perl cpan-libxml-libxml-perl cpan-libxml-rss-perl
libbarcode-code128-perl libclass-returnvalue-perl libdata-ical-perl libdigest-perl libfile-temp-perl
libgd-barcode-perl libgd-gd2-noxpm-perl libhtml-scrubber-perl libnet-z3950-zoom-perl
libpdf-reuse-barcode-perl libpdf-reuse-perl libschedule-at-perl libtext-vfile-asdata-perl
The following NEW packages will be installed:
cpan-libalgorithm-checkdigits-perl cpan-libansicolor-perl cpan-libbiblio-endnotestyle-perl
cpan-libbundle-kohasupport-perl cpan-libcgi-perl cpan-libclass-adapter-perl cpan-libconstant-perl
cpan-libdata-dumper-perl cpan-libdigest-md5-perl cpan-libexporter-perl cpan-libgetopt-long-perl
cpan-libhtml-template-pro-perl cpan-liblocale-codes-perl cpan-libmime-base64-perl
cpan-libmodule-pluggable-perl cpan-libparams-util-perl cpan-libperl-ldap-perl cpan-libpod-parser-perl
cpan-libscalar-list-utils-perl cpan-libsms-send-perl cpan-libtest-manifest-perl cpan-libtest-simple-perl
cpan-libtext-csv-perl cpan-libtext-csv-xs-perl cpan-libtext-tabs-wrap-perl cpan-libtime-hires-perl
cpan-libunicode-normalize-perl cpan-libxml-libxml-perl cpan-libxml-rss-perl libbarcode-code128-perl
libclass-returnvalue-perl libdata-ical-perl libdigest-perl libfile-temp-perl libgd-barcode-perl
libgd-gd2-noxpm-perl libhtml-scrubber-perl libnet-z3950-zoom-perl libpdf-reuse-barcode-perl libpdf-reuse-perl
libschedule-at-perl libtext-vfile-asdata-perl
0 upgraded, 42 newly installed, 0 to remove and 39 not upgraded.
Need to get 3046kB of archives.
After this operation, 23.6MB of additional disk space will be used.
Do you want to continue [Y/n]?


The trick thing is, it will use the packages in the main debian repo first (like libfile-temp-perl above) and then use the package built from cpan if it can’t find one (like cpan-libtest-manifest-perl)

Ive only built packages for amd64 at this point (well a lot are architecture independent), but if others would find it useful I can add i386 packages to my repo as well.