If your goal is to get lean...you could do this in concert with resistance training and adequate nutrition.
A bonus would be to do it 1st thing in the AM..then again right after you resistance train...both times you are glycogen depleted so fat is more likely to be burned.
However it is far better to think of the cardio as a way to optimize cardiorespiratory function...not to burn fat...
You can burn more fat 24 hours a day when you are not doing cardio than you can in 45 minutes to 90 minutes of cardio...and you are likely to lose some muscle in the extended cardio.
Losing fat:
http://www.discussbodybuilding.com/For_Losing_Fat/m_111175/tm.htm