WiFi is a wireless network standard (IEEE 802.11) that is used to access a network without wires. If that network is connected to the internet, then you can access the internet through it. There are three versions: 802.11b, 802.11g, and 802.11a. 802.11b has been around for a while, and is the most popular. It operates on the 2.4 gigahertz band (same as some cordless phones and most microwaves), runs at 11 megabits per second, can be encrypted, and has a range of 300 feet line of sight. 802.11g also operates on the 2.4GHz band, but has a data speed of 54mbs, and can be used with both 802.11b and 802.11g access points. 802.11a operates on the 5GHz band (it gets less interference), has a 54mbs data speed, but can only operate with 802.11a access points. However, many companies make "hybrid" cards that work with 802.11b and 802.11a.
You must be within about 300 feet and have a direct line of sight to the wireless access point to access the network. If the signal has to go through walls, then obviously the range will suffer. If there is a wireless access point in the middle of a lake, and you get a signal, then yes, you can get to the network, which may or may not be connected to the internet.
http://www.linksys.com/edu/
