I'll also add my own personal experience to this...In 2003 I did about an hour of cardio for a year straight before a show (it wasn't on purpose for the show - its just what I was doing). I was healthier for it no doubt - and was able to eat more without putting on fat.

But in the end, it was my legs that was always lacking back then. Doing cardio for an hour a day will reduce your intensity in your leg workouts (even though you may think you have all the energy to get an awesome leg workout - your leg workouts would be that much better without it at this point)...

I'd suggested getting 10-15 minutes in at very low intensity just as a warmup for your workouts. Aside from that, use up your energy in the weight room.