Hi! I am new to the world of networking so I need some help from all you experts out there.
I want to build a wireless network connecting all the computers at my home. I have 3 computers ( 2 desktop PC, one Laptop ). One desktop PC is connected to the internet via ADSL broadband(wired) while the other PC does not have an internet connection. My laptop has in built Wi-Fi receiver. Please guide me on the appropriate hardware I need to buy and software I need to install for the following:
1] The internet connection should be shared by all three computers.
2] I should be able to transfer files from the hard disk of one computer to that of any other computer without involving my ISP. ( I should not be paying my ISP for the data I transfer from one computer to another computer in my home network.)
3] Other computers outside my home should not be able to access my network.
If you need to get in touch with me you can e-mail me at avee_kothari8@hotmail.com.
Any suggestion, tip is welcomed.

Waiting for a reply.
Thank You for the help.

one wifi router
one wifi nic

-cable--one PC
~~wireless~~second PC you bought the NIC for
~~wireless~~laptop with built in wifi nic

Well you will Definitely need a Wireless Router. The best make is Linksys, yet is the most expensive, while there are other companies out there, such as Netgear, D-Link and Belkin. Belkin aren't as good as the others but are cheaper.
Then you will Need a Wireless Adapter for any computer which is not already wireless. I would recommend getting Type G Wireless Equipment, seeing as you can then use any USB adapter with G equipment.
Software for the various items usually comes with the product, it can also be downloaded from the producers if required.
Setting up a wireless network can be done with the Windows tools pre-installed, they are simple to follow using the Wizards.
Also to make you network, use the software provided by the router manufacturer, to use WPA security. Also set this up on windows. WEP security is basic and shouldn't be used.
Any other questions, please post back.