Hi Chandak,
Wireless networks today are pretty simple to setup All you need is an internet connection, an access point, and a wireless nic for each client. You can get an acces spoint one that supports 802.11a or b or Wireless G and I think there is a newer one now. There are distance differences in signal between a, b, and G.
All you really need to do is buy an access point and configure it by the instructions in the manual. Most people fire and forget the things right out of the box but it is ill advised. They are wide open out of the box and anyone driving by can hop on your network.
Use WEP encryption for security. It requires a key to be entered in the config of each client and may be an inconvenience for users but it drastically improves security.
After you buy an access point make sure you get the latest firmware available for it from the manufacturers web site.
Depending on how spread out the 15 homes are you might need multiple access points. You can bridge most of them together to logically extend the range of a single WLAN.
This link might help:
www.maximumpc.com/how_to/reprint_2004-01-05.html
