It's apt-get repositary. You can simple add to /etc/apt/sources.list 
such line:
	deb http://www.pdmi.ras.ru/~theo/debian unstable/
and install every packages from this repositary in such way:
	apt-get update && apt-get install packagename

Of course, you can download a package by hands and install it using 'dpkg -i'.

(c) Theo, theo at myxomop.com.
May 2003