My Network Informer in Google Play
It is simple tool to check your wifi details including your router MAC address, your IP address, etc.
You can save the output to a text file and access it with any file browser
and text editor.
The application is free and it is for Android only. Maybe some day
I will do something similar for iPhone too.
End-user License Agreement:
This application is provided AS IS and if you download and install it,
you do it on your own risk.
I shall bear no responsibility for any damages it can cause
(though I believe it will hurt neither you nor your device,
but I must stipulate these words, you know.)
I will try to update the application in case bugs are found,
but I do not accept any responsibilities.
The application does not collect any personal information.