I have been exercising on an elliptical rider for 1 hour a day, 6 days a week, for a month. I also do toning exercises 2-3 times a week. I have tracked every bite I have eaten also. I had two babies in 13 months. I gained 100+ pounds. Since Jan 30, 2006 I have lost 9 lbs, but only in the first two weeks. The last two weeks I gained and lost the same 2 lbs. I keep my calorie intake around 1500 a day and each work out I burn between 800-900 calories. Why have I already stopped losing weight? I weigh myself once a week, first thing Monday morning.

Hi,
Congratulations on the 9 lbs.
It's only been 4 weeks or so, and the body does "re-adjust" itself; meaning you might gain a pound or two in one week, then lose a pound or two the next.
After a period, after the body system "evens out", you might start to lose more weight.
If you don't already have a good set of scales, maybe weighing to the nearest 1/2 lb, and usually costing around $50 from Walmart or other large department store, the scales themselves could fluctuate. Most cheap bathroom scales only weigh to a pound, and aren't that reliable.
Hang there, and hopefully you will start to lose weight again, but might take another month. I am not a Doctor, nor a Professional in this area; just a person with experience in trying to lose weight or gain over the last many years.

Maybe you are developing muscles. Muscles are heavier than fat. You may not lose weight but you gets leaner and toner. Try recording inch loss instead on specific parts of your body.