How many different types of wireless networks are there?

The most popular "types" of wireless networks are B, G, and N, each having 11 channels (frequencies) therein on which to send and receive data.

• 802.11a

  The first publicly available iteration of WiFi, this standard operates in the 5GHz range and offers speeds of up to 54Mbps.

• 802.11b

  The most popular and pervasive version of WiFi, this standard operates in the 2.4GHz range and offers speeds of up to 11Mbps.

• 802.11g

  The most recent of the 802.11x standards, signal is in the 2.4GHz range and speeds of up to 54Mbps are attainable.

• 802.11n

  Not yet ratified, 802.11n offers both increased range and bandwidth, some proposals work at up to 540Mbps, though the goal of the standard is only 100Mbps. Some companies now offer products adverstised as "Pre-N" which means that the security features being discussed for use in 802.11n are in use on whatever device they happen to be selling. In order to take advantage of said security features, you must be using not only an Access Point that is Pre-N, but but also WiFi adapters that are Pre-N