1. on debian based systems install apt-mirror
   apt-get install apt-mirror apache2
2. edit /etc/apt/mirror.list
   set base_path      /home/apt-mirror
3. create folders
   mkdir /home/apt-mirror/skel
   mkdir /home/apt-mirror/mirror
   mkdir /home/apt-mirror/var
4. run apt-mirror and download all
5. create virtual folders for apache
   mkdir /var/www/apt-mirror
   cd /var/www/apt-mirror
   ln -s /home/apt-mirror/mirror/ftp.de.debian.org/debian/
6. configure apt clients
   edit /etc/apt/source.list
   deb http://your-server/apt-mirror/debian/ squeeze main contrib non-free

list of distros:

debian 8 unstable: Jessie
debian 7: Wheezy (~ 106 GB)
debian 6: Squeeze (~ 61 GB)
debian 5:Lenny
debian 4: etch
ubuntu 10.04 (LTS): Lucid
ubuntu 10.10: Maverick
ubuntu 11.04: Natty
ubuntu 11.10: Oneiric
ubuntu 12.04 (LTS): Precise
ubuntu 12.10: Quantal
ubuntu 13.04: Raring
ubuntu 13.10: Saucy
ubuntu 14.04 (LTS): Trusty
ubuntu 14.10: Utopic