Here is a start:
http://wiki.freeswitch.org/wiki/IVR
http://docs.freeswitch.org/group__switch__ivr__menu.html
http://wiki.freeswitch.org/wiki/Misc._Dialplan_Tools_ivr
http://wiki.freeswitch.org/wiki/Freeswitch_IVR_Originate
http://wiki.freeswitch.org/wiki/Mod_commands
Best regards,
-E
Gpro.ws