I am currently losing fat at an incredible rate simply by doing 30 mins a day 6 days a week alternating between upper and lower body.
15 mins eliptical trainer at level 12 (out of 16, may vary) burning 350 cals
15 mins of chosen body part weights and toning programme. I keep this as intensive as possible by removing gaps, i.e. shoulder press 10 reps, biceps 10 reps, back to shoulder etc. It's important that if you do alternate like this you must use different muscles so you don't strain one muscle.
I tell you what, this intensive 30 min programme (excuse the spelling, i'm english

is much more effective than doing 1 hour of cardio and you lose none of your lean body mass

Also it means you are more likely to do it because you only have to pump the cardio for 15 mins at a time. It's important that you don't take too many long breaks after the cardio, however, because you need to get the heart benifit from the weights and toning part as well.
Hope this helps.
Experts, please correct me if I'm wrong
(just a newbie myself)