+1 to Strollin's Computer Wifi Gateway method if adding a wireless access point for wifi direct from internet connection is out of the picture. Such as if a laptop had a 3 or 4G connection and you wanted to share the internet connection with other devices, then adding a wireless adapter and setting up the computer to share as a gateway connection could be done.
If you have ability to add a wireless access point or wireless router, then doing that would be a better solution, but i am guessing thats not an option and instead need to set up internet connection sharing through the PC and a wireless NIC. The computer would need 2 network adapters last I knew. One that connects to the internet and the other to connect to other devices with the computer acting as the gateway.
I havent messed with setting anything like this up since Windows XP and connecting a single computer to a dial-up connection and sharing that internet connection over Cat5 100mbps peer to peer network with another computer as a gateway connection many years ago when dial-up was all my area had 16 years ago and both my wife and I wanted internet connection without the cost of adding another phone line and paying for another AOL account. When one or other was bringing up a web page it wasnt that bad. But when both were bringing up webpages at the same time it was slower through the dial-up straw connection to the WWW river of data.
