nico:/etc/puppet/manifests$ ls -R
.:
classes  os  site.pp

./classes:
apache.pp  dns.pp       mount.pp  puppet.pp  staff.pp      xen.pp
apt.pp     firewall.pp  munin.pp  snmpd.pp   sudo.pp
common.pp  ipbx.pp      ntp.pp    squid.pp   syslog-ng.pp

./os:
debian.pp  freebsd.pp  openbsd.pp
nico:/etc/puppet/manifests$ head -2 site.pp 
import "classes/*"
import "os/*"

nico:/etc/puppet/manifests/classes$ grep class apache.pp 
class webserver::apache2 
class webserver::zend
class webserver::pool