Wi-fi is pretty much wireless internet. Wireless is such a vague term, for all I know someone could say wireless and be referring to something without wires. :-s Ethernet (in its most common usage of the word) is referring to the connector on the back of your computer/router/modem that looks like this: If you have a wired network at your house, you have the DSL or cable model connected to a wired router with an ethernet cable. You would then use an additional ethernet cable to connect a computer to the router. The numbers and letters refer to wha type of wireless connection the router and wireless receivers are. 802.11b is an old and slow kind that no one uses anymore. Most wireless networking stuff nowadays is 802.11g, which has a maxium data rate of 54Mb/s. 802.11g is backwards compatible with 802.11b, meaning that if you have an 802.11g router and an 802.11b wireless network adapter, they'll work with each other (though of course at 802.11b speeds). The new kid on the block is 802.11n, which is supposed to be rly fast. :-s