The AA on ITS uses the IOS based IVR and scripting applications. The AA for ITS is basically a pre-written script and recorded set of announcements (in US english) that you copy on to the routers flash, with a bit of config off you go...
Do a search on CCO for "IVR TCL" to get loads of info. Or check the below URL for a good overall description of what it is and how it works.
http://www.cisco.com/en/US/partner/products/sw/iosswrel/ps1835/products_configuration_guide_chapter09186a0080080ab2.html
Once you've had a look at the overall IVR TCL info the readme should make more sense, but I do see what you mean - I'd say about as thin as a thin thing could be!
Incidentally, you can use this feature as a generic front end for CCM to provide AA functionality on an IOS router if you want - the search picks that up!
