Cemetary, are you talking about low-impact
exercise -- or maybe both? Low impact = less stress on joints and feet. Low intensity = lower heart rate and less gasping for breath etc. You can do low-impact, high-intensity exercise (like spinning) or low-impact, low-intensity exercise (like walking). I'm not quite clear on which one you're wanting to do -- sorry!
If your concern is the impact on your joints like your feet and knees, good exercises would be a bike, elliptical, or swimming. You can get a terrific workout without impact! I know, because it's the only way I can work out due to bad knees (I'm an elliptical queen).
If you're looking for an easier, lower heart rate kind of exercise, you can do any of the low-impact ones that I listed above at a lower intensity (lower heart rate) by easing up and not pushing as hard. Or you can try walking, which is higher impact than biking, swimming, or elliptical but generally keeps your heart rate lower.
Many people here at 3FC have been successful with walking as their main exercise!
A lot of members love the Walk Away The Pounds tapes (WATP) and there are whole threads devoted to them. If you walk outside or on a treadmill and ever want to increase the intensity, it's easy to throw in a few intervals of easy jogging and then go back to walking. It's such a versatile exercise and you can do it anywhere.
The most important thing is for you to find an exercise that you enjoy and will stick with over the years. Give walking a try ... you may fall in love with it.