I don't belong to a gym, and at the present, I don't have enough money to buy exercise equipment, so I was wondering if there are some other exercises I could be doing that I'm not...?

Currently, 5 or 6 times a week, I do a combination of jump rope and jumping jacks for 25 minutes, push-ups, and sit-ups.

My goal (for now) is just to lose 10-15 pounds of body fat and to tone up so my muscles are more defined.

If anyone has any recommendations, I would appreciate it. Thanks.

Well I'd reccommend running or High Impact Interval Training instead of jumping jacks, but it's your call I guess.

Make sure your letting a days rest between the days you do pushups and situps, as you need to let your muscles heal.

Other muscle building exercises you can do without equipment are Pullups, chinups, body weight squats, cat stretches, dips, and calf raises.

Just reply if you're not sure on how to do some of the techniques.

Thanks for responding, Hoyd.

I've actually been considering that maybe I should start jogging at least two days a week and gradually increase it over time.

I am familiar with all the exercises except dips, calf raises, and cat stretches. If you could tell me about them, I would appreciate it.

Thanks again.

To perform a dip you would get two objects about as high as the bottom of your chest (possibly two chairs or something), and you place the parallel to each other, get between them and raise yourself off the ground for a set of how many ever you want to do. You should feel it in the triceps and to a lesser extent the chest. (it's reccommended that you bend your knees so you don't hit the gound, also make sure your objects are stable, have them cave inward in mid raise si not fun)

For calf raises you just stand straight with your feet at about shoulders width apart and raise up on the tip of your toes. You can also point your feet inward or outward to work the muscle at different angles.

The cat stretch is kind of ahrd to explain if you're not familir with it. It's based upon the yoga exercises "upward dog" and "downward dog". U.S. Navy Seals also employ it in their fitness routine, they call them "dive bombers".
You start on your hands and feet with your butt high in the air, your body should be at a 45 degree angle, then slowly and smoothly swing your body forward so your stomach and knees are supported by your toes just off the ground, you should swing all the way through so your looking at the ceiling. Don't let your knees or stomach hit the ground, this takes the weight off your arms, shoulders, and chest. Those are the muscles that are targeted.
Also swing back to the starting postion, don't get out of the form to come back to it.

Thanks. I'll try those exercises that you recommended.