Make sure your diet is as clean as it can be (already posted here - I know you know that!!). That's very important. But make sure on your cardio days you are "mixing" it up a bit. Make sure you do a variety of cardio -- not just treadmill, running, etc.. Include some high intensity stuff in there as well (such as one of the Imaxes, Cardio Fusion, too many to name). Not sure what DVDs you have, but I get the best results when I rotate my cardio. I'm also doing STS, so on my "off" days I'll do step one day (did Body Max 2 step this week), Kick Box another (4DS Kickbox, and then treadmill or bicycle work. I've seen that this is good for ME to see results (we're all different). I also mowed the grass today (I don't have a huge yard, so it wasn't THAT much of a cardio workout), but I went ahead and included that in my workout schedule (good thing because I had to go back to work and after taking several phone calls, etc., I didn't have time to work out!). Make sure there is variety in your workout since your body adapts to certain workouts over a period of time.
Also the scale can be deceiving -- trust me! I can gain or lose 5 pounds in a day, so I know it's water weight when this happens. Also for me, it's hard to gauge my weight loss with the way my pants fit because some days the scale doesn't say I'm overweight, but my pants say I am! This is just because I'm carrying extra water weight (something I've always done!). It's frustrating. Just keep doing what you are doing -- the good thing is, is that you notice the changes and so do other people. I wish you the best of luck -- keep us posted on your progress!
Julie