Wireless Internet access is growing at a furious pace in developing economies like India and China, South America and many other places in rest of the world. The basic standard for this wireless technology is WiFi. WiFi is primarily used to create a Local Area Network (LAN), which allows users within the network to connect wirelessly. The commonest use is primarily in Internet connectivity, but WiFi is also used for closed-circuit business networking and for connecting consumer electronics, such as TVs and DVD players.
WiFi makes connecting to the Internet within a home or business cheap and easy. While WiFi technology has proved largely successful in providing cheap wireless Internet service within close proximity to the WiFi access point, a new technology, WiMax, could expand the potential of wireless penetration and connection quality. WiMax does provide wireless reception over significantly greater distances, and at higher broadband levels. But the technology behind WiMax is significantly different from WiFi, as well as more costly. WiMAX is an acronym for World Wide Interoperability for Microwave Access.
To Sum it up...
# WiMAX is a long range (many kilometers) system that uses licensed or unlicensed spectrum to deliver a point-to-point connection to the Internet from an ISP to an end user. Different 802.16 standards provide different types of access, from mobile (analogous to access via a cellphone) to fixed (an alternative to wired access, where the end user's wireless termination point is fixed in location.)
# Wi-Fi is a shorter range (range is typically measured in hundreds of m) system that uses unlicensed spectrum to provide access to a network, typically covering only the network operator's own property. Typically Wi-Fi is used by an end user to access their own network, which may or may not be connected to the Internet. If WiMAX provides services analogous to a cellphone, Wi-Fi is more analogous to a cordless phone.