The next you might want to do is to enable WEP (wireless equivalent privacy) security on your router. If your router has 128 bit encryption use it. This is more secure than 40 bit encryption, unless you have any other routers that are older. If not, then settle for the 40 bit encryption instead.

You will need to enter the corresponding WEP encryption key on all of your computers that connect wirelessly. Reboot the router and verify you can still connect with the network cable removed. It would be easier to make all of the changes at once and the reboot, but if you make a mistake doing it step by step helps you find your mistakes easier.

The next step is changing the SSID (Service Set Identifier). The first thing you should do is change the name from its default setting. If your router lets you disable the SSID broadcast you should. Again make the corresponding changes on each of the computers that connect wirelessly and reboot the router. Once the router reboots make sure you can still connect to the network.

Then you should allow access through Mac addresses. Each computer has a unique Mac address that looks like 0A-3C-2A-55-E4-A0. Get all of the MAC addresses of all of the computers that connect wirelessly and restrict access on the router to only those Mac addresses. Reboot the router and verify you can still connect.

Although these tips will not keep out sophisticated professional hackers they will keep out casual snoopers. Lastly on each computer make sure you are sharing only the folders that you want other people to be able to see.