I need to find password for my wifi router which is connected already.I'm using macbook pro os x lion.Any guidance please.
If the password is stored, you can find it using the program Keychain Access.
If you open
Double-click the name of the network you are using (if you don't know the name of the network, you can find it in the WiFi menulet (looks like a quarter of concentric circles toward the right side of your menu bar).
Check the Show password box, enter your system password, and click the Allow button.
That should show you the password for the wireless network you are on, if it is stored on your computer. If no such entry appears, it means the password is not stored on your computer.
Spotlight → Keychain Access → type Wi-Fi name →