Возможно,кому-то будет полезным.

Ubuntu:

deb ftp://ftp.mgts.by/pub/ubuntu/ gutsy main restricted universe multiverse
deb ftp://ftp.mgts.by/pub/ubuntu/ gutsy-security main restricted universe multiverse
deb ftp://ftp.mgts.by/pub/ubuntu/ gutsy-updates main restricted universe multiverse
deb ftp://ftp.mgts.by/pub/ubuntu/ gutsy-proposed main restricted universe multiverse

Debian:

deb http://ftp.byfly.by/debian/ lenny main contrib non-free
deb-src http://ftp.byfly.by/debian/ lenny main contrib non-free
deb http://ftp.byfly.by/debian-multimedia/ etch main contrib non-free
deb http://ftp.byfly.by/debian-security/ lenny/updates main contrib non-free
deb http://ftp.byfly.by/debian/ etch main contrib non-free
#deb http://ftp.byfly.by/debian/ unstable main contrib non-free //для "аццких" =)
deb http://ftp.byfly.by/debian/ experimental main contrib non-free

aptitude install debian-keyring debian-archive-keyring
gpg --keyserver subkeys.pgp.net --recv-keys ключ_на_который_ругается
gpg --export --armor ключ_на_который_ругается | sudo apt-key add -
aptitude update

писать в
/etc/apt/sources.list