Howtoforge published a tutorial: How To Create A Local Debian/Ubuntu Mirror With apt-mirror
This tutorial shows how to create a Debian/Ubuntu mirror for your local network with the tool apt-mirror. Having a local Debian/Ubuntu mirror is good if you have to install multiple systems in your local network because then all needed packages can be downloaded over the fast LAN connection, thus saving your internet bandwidth.How To Create A Local Debian/Ubuntu Mirror With apt-mirror