I would like to be notified via email when someone is logging-in to Joomla Administration interface as Superuser, and also know his ip address.
Is it possible?
Yes, it is possible with 3rd party extensions.
Assuming you're looking for a free one, maybe try something like User Login Tracking. It send you an email, and stores the following data:
You may also want to look at JSecure Lite which I think provides similar features.
On a such question, it's not possible to not mention Admin Tools by Akeeba. It provides an application firewall, where you can adjust such and even more settings that will enhance the security of your Joomla site.
You can set it to notify you when anyone is logging-in and record its ip. It can also track un-successful login attempts and store the failed credentials.
It comes in 2 versions free and commercial (can't remember the exact features of each version).