How to setup your Wireless Router to be secure (Linksys router)

There are 4 basic things you need to do (this is for Linksys routers):
1 -Set the Security Mode to WEP, i.e. enable encryption. This insures all network traffic on your network is encrypted. This makes it harder for someone who is sniffing your communication to intercept traffic and obtain sensitive data that you want kept private, like passwords. WEP allow a group of devices on a local network (such as a home network) to exchange encoded messages with each other while hiding the contents of the messages from easy viewing by outsiders. All devices need to have matching keys.
2- Disable Wireless SSID Broadcast - Most routers automatically transmit their network name (SSID) into open air. This feature is intended to allow clients to dynamically discover and roam. However, this also makes it easier for hackers to break into your home network. Because SSIDs are not encrypted or otherwise scrambled, it is easy to grab one by snooping. Knowing your SSID brings hackers one step closer to a successful intrusion. In a home Wi-Fi network, roaming is unnecessary and the SSID broadcast feature serves no useful purpose. You should disable this feature to improve the security of your WLAN.
3 -Enable the wireless MAC Filter. Without MAC address filtering, any wireless client can join (authenticate with) a Wi-Fi network if they know the network name (SSID) and perhaps a few other security parameters like encryption keys. When MAC address filtering is enabled, however, the access point or router performs an additional check on a different parameter. Only machines in a list of allowed MAC addresses (PCs) can join the network. To improve the security of your Wi-Fi LAN, you should enable and use MAC address filtering.
4 - Change your router's password from the default. Every Linksys router comes from the factory with a default username and password which are well-known. So if you dont change it, anyone can potentially log on to your router. People know this. You should change it to something else to make it harder for someone to access your router's admin settings.

Here is how you do each:
(First, navigate to http://192.168.1.1 using your browser to get to your router's settings page.)
Set the Security Mode to WEP
Go to the Wireless, Wireless Security, Set the Security Mode to 'WEP'
Click the 'Generate' button to generate some WEP keys.
You will then need to enter at least one matching WEP key into each PC that you want to connect to your network. You can do this via the wireless configuration on the PC.
Disable Wireless SSID Broadcast
Go to the Wireless, Basic Wireless Settings, Select 'Disable Wireless SSID Broadcast'
Enable the wireless MAC Filter
Go to the Wireless, Wireless MAC Filter, Select 'Enable'
Select 'Permit only PCs listed to access the wireless network'
Click the button for 'Edit MAC Filter List'
Add the MAC addresses of any PCs that you want to allow to connect to your network
To get the MAC address of a PC, open a command window and type 'ipconfig /all'
Change your router's password from the default
Go to Administration, Management and reset the Password.

Useful reading:
http://compnetworking.about.com/cs/wirelessproducts/qt/disablessidcast.htm
http://compnetworking.about.com/cs/wirelessproducts/qt/macaddress.htm
http://compnetworking.about.com/od/wirelessfaqs/f/wep_keys.htm
http://lifehacker.com/software/wireless/a-beginners-guide-to-setting-up-a-wireless-network-243133.php