To simply create a nice cowbuilder environment for lenny within atlas just use:
cowbuilder --create --distribution=lenny --debootstrapopts --arch=amd64 --basepath /var/cache/pbuilder/base.amd64.cow \
--othermirror="deb http://n0.aei.uni-hannover.de/debian lenny-proposed contrib|\
deb http://n0.aei.uni-hannover.de/debian lenny contrib|deb http://repository/reprepro lenny contrib|\
deb http://ftp2.de.debian.org/debian lenny main contrib non-free"
and
cowbuilder --create --distribution=lenny --debootstrapopts --arch=i386 --basepath /var/cache/pbuilder/base.i386.cow \
--othermirror="deb http://n0.aei.uni-hannover.de/debian lenny-proposed contrib|\
deb http://n0.aei.uni-hannover.de/debian lenny contrib|\
deb http://ftp2.de.debian.org/debian lenny main contrib non-free"
--
CarstenAulbert - 09 Jul 2009