I just bulid my own repository today containint all my an my roommates kubuntu and ubuntu packages. Not the ones from the installation but the ones downloaded with apt. I followed this howto: http://www.debian.org/doc/manuals/repository-howto/repository-howto
I mountet an external harddisk at /home/anta/repo
I added the packages downloaded with apt. These are in /var/cache/apt/archives. Those i put in: /home/anta/repo/dists/breezy/main/ Then (so apt can read the repo):
mkdir /home/anta/repo/breezy/main/binary-i386
I also added the packages from the ubuntu install cd locate in /media/cdrom0/pool. Those are in /home/anta/repo/dists/breezy/cd/
mkdir /home/anta/repo/breezy/cd/binary-i386
and finally build the repository:
dpkg-scanpackages dists/breezy/main/ /dev/null | gzip -9c > dists/breezy/main/binary-i386/Packages.gz
dpkg-scanpackages dists/breezy/cd/ /dev/null | gzip -9c > dists/breezy/cd/binary-i386/Packages.gz
Then the repository can be added:
deb file:/home/anta/repo/ breezy main cd