debian6 install flash plugin

1. add to /etc/apt/sources.list

deb http://ftp.uk.debian.org/debian/ squeeze main contrib non-free
deb-src http://ftp.uk.debian.org/debian/ squeeze main contrib non-free

deb http://security.debian.org/ squeeze/updates main
deb-src http://security.debian.org/ squeeze/updates main

2. update

sudo apt-get update

3. install

sudo apt-get install flashplugin-nonfree