|The password or key is the WEP or WPA security encryption key or passphrase.|
If you do not know it how does any other wireless device connect? If you did not set it in the router then ask who-ever did.
Of course the enxryption password will be visible if you log into the router admin interface from a wired PC, using the admin login user ID and password. Again , ask the person who configured the router.
Goin' Fishin' (Some day)