New Zealand
I have just returned from doing the Tongariro Crossing in the North Island.
This company provides a guided crossing in the winter, when the snow requires a guide for all of those but the most experience. In the summer they will take you to the base camp and pick you up on the other side.
As oppose to other agencies they have got a concession from the maori iwi that allows them to do the full crossing. Be aware of other agencies that may take you to the top but you will have to return the same way back
www.tongariroexpeditions.com/
My account of the day
adegreeaday.blogspot.com/2009/07/mount-doom-and-one-ring.html
Search Been there