When I run sudo apt-get update I have the following output:Hit http://mirror.transact.net.au stable Release.gpgIgn http://mirror.transact.net.au/debian/ stable/contrib Translation-enIgn http://mirror.transact.net.au/debian/ stable/contrib Translation-en_AUIgn http://mirror.transact.net.au/debian/ stable/main Translation-enIgn http://mirror.transact.net.au/debian/ stable/main Translation-en_AUIgn http://mirror.transact.net.au/debian/ stable/non-free Translation-enIgn http://mirror.transact.net.au/debian/ stable/non-free Translation-en_AUHit http://mirror.transact.net.au stable Release             Hit http://mirror.transact.net.au stable/main amd64 PackagesHit http://mirror.transact.net.au stable/contrib amd64 PackagesHit http://mirror.transact.net.au stable/non-free amd64 PackagesGet:1 http://www.debian-multimedia.org squeeze Release.gpg [198 B]Ign http://www.debian-multimedia.org/ squeeze/main Translation-enIgn http://www.debian-multimedia.org/ squeeze/main Translation-en_AUIgn http://www.debian-multimedia.org/ squeeze/non-free Translation-enIgn http://www.debian-multimedia.org/ squeeze/non-free Translation-en_AUGet:2 http://www.debian-multimedia.org squeeze Release [22.0 kB]Ign http://www.debian-multimedia.org squeeze ReleaseGet:3 http://www.debian-multimedia.org squeeze/main amd64 Packages [72.8 kB]Get:4 http://www.debian-multimedia.org squeeze/non-free amd64 Packages [3,902 B]Fetched 98.9 kB in 3s (32.6 kB/s)   Reading package lists... DoneW: GPG error: http://www.debian-multimedia.org squeeze Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 07DC563D1F41B907I've scoured the web but can only find esoteric solutions I cannot understand.  Is there a way to bypass the security feature blocking it without engaging in esoteric commandline?
Security hurdles to enabling sources in repo
repository
As you can find on the Debian Multimedia home pageThe first package to install is debian-multimedia-keyring.Since Squeeze you can install this package with apt-get but you need to press Y when the package ask what to do and do not press return. So, summing up, don't care about apt-get update warning, install the named package and answer Y when asked.