I've been doing over an hour of exercise everyday, and I want to make sure it's going to be effective enough cardio to burn fat.

I have one exercise DVD I'm gonna be doing a few times a week. But on those other days, I've been turning on some great tunes and marching along, walking in place, switching to higher tempo songs and lower tempo songs. Sometimes I'll "run in place" along to the beat or melody of a song. I'll move faster or slower depending on the song. Sometimes I'll do knee lifts. All the while I'm holding little 1 lb hand weights. I've started strength training as well, doing bicep curls with a 5 lb weight and ab exercises and etc etc.

At the end of my cardio session, I am usually sweaty, and all the muscles in my legs have been sore. Does this mean I'm burning off calories? Or is my cardio not as effective as I think?

We "burn calories" just by being alive...How effective (or ineffective) your way of exercising is will show up in inches lost and pounds shed. Good luck and keep moving!

Well, that's about what a Leslie Sansone walking workout is: marching in place, kicks, knee raises, kick backs, side steps.
If you're sweating and breathing hard, I'd say it's a good workout, but the only way to be sure is to check your heart rate and make sure you're in the zone for fat burning.
Do a google search and you should find the calculation to figure it out.
A heart rate monitor is a neat toy to have and it can tell you your heart rate during exercise and how many calories you burned.

There's some debate about how long you should do cardio. I *personally* have decided to not do over 30 minutes. The amount of calories burned is negligible (sp?), and to me it becomes boring after 30 minutes.

Good luck to you