You might also hear about some other wireless standards, and wonder how they are related to Wi-Fi. The two other wireless standards you are most likely to hear about are Bluetooth and 3G.
Bluetooth is a short-range connectivity solution designed for data exchange between devices such as printers, cell phones, and PDAs. Like 802.11b, it uses the 2.4GHz spectrum. Although Bluetooth is built into a great many devices, it is a standard with some severe disadvantages, mainly that it is far slower than 802.11b (with nominal throughput of up to 721 Kilobytes per second) and with a maximum range of about 30 feet (compared to Wi-Fi's unamplified range of several hundred feet). Bluetooth's main claim to fame is that it is inexpensive, which is why it has been added to so many devices.
3G is a catch-all term for a proprietary network using spectrums leased by telecommunications carriers such as Sprint and Verizon. Although 3G would undoubtedly transmit data at faster rates than Wi-Fi perhaps at rates as fast as 384Mbps there is no doubt that users would be expected to pick up the tab. (After all, it uses a leased spectrum that is not free for the telecommunications companies.)
At this point, there is very little in the way of completed 3G infrastructure, nor is there any reason to expect 3G technology to be used as the backbone for ad-hoc wireless networking in the way Wi-Fi has.