Where can i find a reliable and easy to use ivr (INTERACTIVE VOICE RESPONCE) software/system for my Business?

A friend of mine has an irv system which he uses for his business, i run a similar business and i require a similar ivr telephone system for my business, i am talking about the sort of ivr system that works like regular telephone banking were clients would call and be asked to key in a code with there telephone keypad in other to access information, my friend refuse to tell me how he set his up.|||Try NCH Software.