Something like this:
1. Make sure rsync package is installed - e.g., apt-get install rsync
2. If you want to run it out of xinetd, make sure xinetd is installed and set to start at boot.
3. Change 'disable' in /etc/xinetd.d/rsync and restart xinetd
4. Setup /etc/rsync.conf like this:
max connections = some number if you want or leave this line out
log file = /var/log/rsync.log
timeout = 300
[some module name]
comment = my awesome repo
path = /path/to/repo
read only = yes
list = yes
uid = some unpriv'd user
gid = some unpriv'd group
5. Make sure 873 is open in iptables