Install

apt-get install pbuilder

Create build environment

sudo DIST=lenny ARCH=amd64 pbuilder create
sudo DIST=lenny ARCH=i386 pbuilder create
sudo DIST=etch ARCH=i386 pbuilder create

Build a package in chrooted environment

sudo DIST=lenny ARCH=amd64 pbuilder build mtr_0.75-2.dsc

Get the results

$ ls /var/cache/pbuilder/lenny-amd64/result/
mtr_0.75-2_amd64.changes
mtr_0.75-2_amd64.deb
mtr_0.75-2.diff.gz
mtr_0.75-2.dsc
mtr_0.75.orig.tar.gz
mtr-tiny_0.75-2_amd64.deb