If you have physical access to a PC, you still cannot get the WLAN password or the DSL dial-up info, since they are not displayed as clear text but as stars.
Excellent little freeware tools let you do it on windows, assuming you kindly asked your friend, or you forgot your own passwords:
Wirelesskeyview shows you the password of currently connected WLAN networks on the PC you run it on.
Dialuppass shows you complete access codes of active DSL/dial-up connections on the PC you run it on.
Ironically: since you retrieve passwords, some antivirus software detects the downloaded program as trojan ("false positive" problematic). Of course I can't guarantee anything, but i didn't get any trojan.
thanks and credits to Nir Sofer