NetResView

NetResView is a free application that allows you to view and know the computers and devices connected to your local network.

When you run NetResView and scan the network you'll view a list of the computers and any other kind of devices (phones, PDAs,...) that are connected to your local network and you'll be able to access information about them: Kinf of device, nconnection provider, name and version of the O.S. and even their MAC.

Finally, you can export the results and save them to check them later.