How to setup an Access Point mode Wi-Fi Hotspot?
Point to be noted: Wireless hotspots aren't the same as ad hoc networks. There is significant difference between the two. In short, ad hoc networks aren't supported on newer devices and most Android, Windows Phone and Blackberry devices (and maybe iOS devices too) whereas AP mode Wi-Fi hotspots are. To get an idea about AP mode hotspots, ad hoc networks and their difference, refer to this Wikipedia page and this article on Connectify website.