Traditionally computers have been put together in Networks with cables using hubs or switches to join them all together. Wireless Networking is exactly the same in concept, except instead of the Ethernet cards & cables we have Wireless Network cards, and instead of hubs and switches we have a wireless access point or wireless router.
The only difference is in the configuration to set up the extra security precautions necessary to prevent your neighbours and people passing by from accessing your network and/or internet connection.

A wireless router is a wireless device that connects one computer or a whole network to another computer or network. It is possible to have a wireless network in your home or office. You will definitely come across wireless networks at most international airports. A wireless network is powered by a wireless router, which is responsible for sending information from one computer to another. The router will help you to share a single Internet connection between two or more computers, which can be on the same floor or even on different floors.

802.11a runs in the 5 GHz frequency range and will allow data speeds of up to 108 mbs. The shorter wavelength of the 5 GHz frequency greatly reduces its range and penetration but it comes into it's own in areas where it might be overcrowded or have other equipment (eg medical) operating in the 2.4 GHz range. Its lower performance and comparatively hefty price tag have made it fairly unpopular in Australia and it's now quite rare to see products on the market utilizing the 802.11a standard.

802.11b operates in the 2.4 GHz frequency range and was an advance that led to wireless networking becoming popular and viable in Australia. It promised throughput speeds of 11 mbs but as with all wireless technologies you can at least halve the manufacturer's figures for true throughput results using a network tool such as Check. Range can be anything up to 100 meters with clear line of sight with most products out of the box but can be extended substantially with aftermarket antennas and boosters.

802.11b+ operates in the 2.4 GHz frequency range and was a variation of 802.11b chipset used by D-Link in particular. It doubled the throughput figures but would fall back to plain 802.11b speeds when used with other wireless standards including the modern ones like 802.11g & n. See also FAQ 2.15 below.

802.11g operates in the 2.4 GHz frequency range and took wireless speeds up to 54 mbs and with a bit more throughput to play with it effectively extended the range a little bit too. It remains a popular and cost effective choice.
802.11g+ operates in the 2.4 GHz frequency range and was a variation on the 802.11g chipsets that effectively doubled the data speeds. However, when used in conjunction with 802.11g or n products it will fall back to standard 802.11g speeds. Wireless 150: operates in the 2.4 GHz frequency range and is a cheaper, scaled down version of 802.11n, allowing speeds of up to 150 mbs when used in conjunction with 802.11n wireless adapters.

802.11n operates in either the 2.4 GHz or 5 GHz frequency ranges or both* (eg products advertised as dual band or tri-mode etc) and at the time of writing allows speeds of up to 300 mbs (but that might even double in the near future). Range is also greatly improved but the corresponding wireless adapters must be used to get anything like the promised performance. See also FAQ 2.20 below.