Before I list what you need to do to secure a wireless router I want to point-out that your home network and computer is not safe just because it is small and incidental. If nothing else, your computer could be used to deliver spam/malware/illegal-pornography to others or it can be used to attack others. If you do ANY ecommerce on line you are vulnerable to having your credit card stolen or id theft. If you have a small business, even if there is no more than a catalog pictures, you are vulnerable to defacement that can ruin your business image. Now onto the list:

1. With a used or rebuilt router, reset it to its factory state.
   Even if you think it's fresh out of the box you really can't be sure what is on the router.
2. Update it with the latest firmware available for the device.
   There may be a delay between when the device was put on the ISP's shelf and when it was sold to you. Check the vendor's web-site to see if there are any new security issues with their device.
3. Reset the default password and use a secure password
   . The password should not be a single word in the dictionary or easily guessed, even if you have added some numbers at the end of the word. There are several sites out there that are dedicated to keeping a list of default passwords and there are programs to test every word with numbers added at the end.
4. Turn off 'remote assistance' or 'remote control'.
   These features let another access the settings in your router and change them as needed. However, if the good guys can administer the router remotely then the bad guys will figure out how to as well.
5. Turn on WPA encryption.
   Do not use WEP. WEP is an out-of-date way to encrypt (scramble) data that can be broken in minutes. Like the article said, there are several tutorials on the Internet on how to do so.
6. Do not use a wireless router for ecommerce
   . A wireless router is convenient. On my own setup, I have wireless available for when I need it, but a wired connection for when I'm doing something important like banking or paying my bills online.

I'm not saying these tips will makes your site 100% secure (nothing will), only that they will help.