Place the following two lines in /etc/dhcpd.conf:
filename ""; option root-path "aoe:eN.M";
where eN.M is the AoE target name that you selected for your target.
You will probably need to restart your DHCP server for the changes to take effect:
root@chipmunk# /etc/init.d/dhcpd restart
Boot your diskless client using gPXE. If all has gone well, you should see it boot from your AoE target image.
Congratulations on a successful boot from SAN!