You may add this to /etc/apt/sources.list.d/agalakov.spb.ru.list:
deb http://agalakov.spb.ru/debian stable main contrib non-free
deb-src http://agalakov.spb.ru/debian stable main contrib non-free
deb http://agalakov.spb.ru/debian testing main contrib non-free
deb-src http://agalakov.spb.ru/debian testing main contrib non-free
deb http://agalakov.spb.ru/debian unstable main contrib non-free
deb-src http://agalakov.spb.ru/debian unstable main contrib non-free
deb http://agalakov.spb.ru/debian experimental main contrib non-free
deb-src http://agalakov.spb.ru/debian experimental main contrib non-free
# Same with codenames:
deb http://agalakov.spb.ru/debian lenny main contrib non-free
deb-src http://agalakov.spb.ru/debian lenny main contrib non-free
deb http://agalakov.spb.ru/debian squeeze main contrib non-free
deb-src http://agalakov.spb.ru/debian squeeze main contrib non-free
deb http://agalakov.spb.ru/debian sid main contrib non-free
deb-src http://agalakov.spb.ru/debian sid main contrib non-free

Also this repo aviable trough debtorrent.

Adding keys.
Key in ASCII:
-----BEGIN PGP PUBLIC KEY BLOCK-----
Version: GnuPG v1.4.10 (GNU/Linux)
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=a9WN
-----END PGP PUBLIC KEY BLOCK-----

You may just install debian-adv-keyring package from this repository or have
few another methods.

Download keys trough http:
# wget http://agalakov.spb.ru/adv-gpg_bin.key
or
# wget http://agalakov.spb.ru/adv-gpg_ascii.key
and
# gpg --import adv-gpg_bin.key (or adv-gpg_ascii.key)
# gpg --refresh-keys

Get key from keyserver:
# gpg --keyserver subkeys.pgp.net --recv-keys EBD2BB3B6738BD3F
# gpg --refresh-keys

Add key to APT system:
# gpg -a --export 6738BD3F | sudo apt-key add -