MII
Hi Guru
Media Independant Interface or MII (nowadays even GMII is used for higher data rates in the range of Gbps) is basically an interface between PHY(physical media) and the MAC(Media access control). It defines a standard so that any physical media can be connected to the MAC i.e. it makes the interface media independant ( n thts y called so).
In other words u can say it defines some standard signals to interface physical media with the MAC. So whenever a h/w designer designs a MAC , he needn't worry abt which physical media will be used. He will just use these standard signals.
U can easily find the details abt actual signals defined in an interface (like MII, GMII, XAUI n many others) . Many articles r there on web.