Creating a backup of the system

[João Silva <a28123@alunos.det.ua.pt>]

Hi all,

how can I create a backup of the system? What I mean is, I have lots of 
packages installed; is there a way to save the list of packages that are 
installed, and then use that list in another computer to create a system 
similar to mine?

I know there is /var/lib/dpkg/status; is there a way to install all the 
packages listed there in a freshly new installed debian system (already 
configured to use apt-get)?

Also, /var/cache/apt/archives is using a lot of disk space; can I 
delete all the files? Or is there any way to clear this cache?

Thanks for your time,

João