View Passwords For Wi-Fi Access Points Saved On Your Android Device

[Costas]

Download Root Explorer

Navigate at directory /data/misc/wifi

read wpa_supplicant.conf file!

on some devices is /data/wifi/bcm_supp.conf

original article
http://www.addictivetips.com/mobile/how-to-view-passwords-for-wi-fi-access-points-saved-on-your-android-device/