Secure Your Wireless Network

No one can intercepts your Wi-Fi traffic,just Follow a few easy steps.

The first line of defense for your Wi-Fi network is Encryption, which encodes the data transmitted between PC and wireless router. Unfortunately, most routers ship with encryption turned off, and many users don't turn it on, leaving themselves completely exposed. If you haven't already, enable your router's encryption, and use the strongest form supported by your network. The Wireless Protected Access (WPA) protocol and more recent WPA2 have supplanted the older and less-secure Wireless Encryption Protocol (WEP).
Go with WPA or WPA2 if at all possible, since WEP is relatively easy to crack. (You have to use the same form on all devices on your network; you can't mix WEP and WPA.) The keys used by WPA and WPA2 change dynamically, which make them nearly impossible to hack. Use a strong password for your encryption key, such as a combination of letters and numbers of 14 characters or more.Make sure you change the default network name and password on your router. Doing so will make it much more difficult for hackers to break into your router and commandeer its settings.
FIREWALL
The firewall built into your router prevents hackers on the Internet from getting access to your PC. But it does nothing to stop people in range of your Wi-Fi signal from getting onto your network--and with the latest high-performance equipment, your Wi-Fi signal could reach clear down the block. Without encryption and other protective measures, anyone can use readily available tools to see all your Wi-Fi traffic.
Secure notebook at public Wi-Fi hotspots
Make sure it's a legitimate hotspot, Nefarious types have been known to set up pirate routers with familiar SSID names like "wayport" or "t-mobile," and then use them to capture unsuspecting users' log-on information and other private data. Verify that your PC's software firewall is turned on, and that Windows' file-sharing feature is off; it's off by default in Windows XP with Service Pack 2. To check this setting, open Control Panel and choose Windows Firewall (you may have to click Security Center first in XP or Security in Vista). In XP, select the Exceptions tab, and look in the Programs and Services to make sure "File and Printer Sharing" is unchecked. In Vista, click Change settings, then select the Exceptions tab and follow the instructions for XP. Never send bank passwords, credit card numbers, confidential e-mail, or other sensitive data unless you're sure you're on a secure site: Look for the lock icon in the bottom-right corner of your browser, as well as a URL in the address bar that begins with https. Such sites build in their own encryption. Always turn your Wi-Fi radio off when you're not at a hotspot: Hackers can use it to create peer-to-peer Wi-Fi connections with your computer and access it directly.