Hi Bob,
In the drop down box if you select WEP-OPEN then when anyone tries to connect to your wireless signal they will need the default WEP key or you can create your own 10 digit number, if you set it as WPA2-PSK you can create your own password to connect to wireless e.g. business10.
Setting the router to use WPA2-PSK is more secure than having it set as WEP-OPEN.
Hope this helps.
Regards
Ryan