wget http://snapshot.debian.org/archive/debian/20100801T150833Z/pool/main/p/php5/php5-fpm_5.3.3-1_amd64.deb
dpkg -x php5-fpm_5.3.3-1_amd64.deb fpm
dpkg -e php5-fpm_5.3.3-1_amd64.deb fpm/DEBIAN/
sed -i 's/php5-common (= 5.3.3-1)/php5-common (>= 5.3.3-1)/g' fpm/DEBIAN/control
dpkg -b fpm/ php5-fpm_5.3.3-1_amd64_patched.deb
dpkg -i php5-fpm_5.3.3-1_amd64_patched.deb
взято тут:
http://www.zagirov.name/debian-testing-install-php5-fpm