Below are a list of charities to give you some ideas:
Latter-day Saint Charities is the humanitarian arm of the Church of Jesus Christ of Latter-day Saints. Through this charity, they provide wheelchairs, clean water, immunizations, neonatal resuscitation training, and more to people in developing countries. Last year, they helped over a million people gain access to clean water through building wells and spring water systems.
International Princess Project. This is a program to help rescue women in India who are enslaved in prostitution. Their mission, as stated on their website is to "Establish self-sustaining enterprises in partnership with indigenous organizations that provide for physical, emotional and spiritual needs of women formerly enslaved in prostitution." One way they do this is to have the women make Punjammies, gorgeous pajama bottoms made with traditional Indian material. The women are able to sustain themselves and make a life outside of prostitution.
Kiva. This is an organization that provides micro-loans to people in developing countries. A woman can sew to provide for her family, if only she could afford a sewing machine. A micro-loan will get that for her, and she will pay back the loan as she is able. On this site, you can actually choose the entrepreneur that you lend to, and loans are only made in $25 amounts. This is doable for everyone and is a way to help people who are trying to help themselves.
Helen Keller International is an organization started by Helen Keller to help prevent blindness and malnutrition. Operating in 22 countries around the world, they help people raise their own nutritional food, provide free eye treatment, and do a host of other things to improve the lives of some of the most impoverished people on the planet.
Against Malaria is a charity that distributes nets to protect people from malaria. Only $5.00 will buy a life-saving net. With 1-3 million people dying from malaria each year (and the hardest-hit being pregnant women and young children) this is such a simple way to help. You can see exactly where your nets are distributed and see videos and pictures of distribution.
The Citizens Foundation is an organization that builds schools in Pakistan and provides opportunities for impoverished children to attend. They strive to maintain a 50% enrollment of girls, believing that everyone is deserving of education, regardless of gender or social standing. Pakistan has an alarmingly high illiteracy rate. With radical fundamentalists offering free meals to entice students into their camps, alternative and healthy education is sorely needed.
GEMS is an organization in the United States that helps girls who have been sexually exploited and trafficked. From their website, "GEMS is committed to ending commercial sexual exploitation and domestic trafficking of children by changing individual lives, transforming public perception, and revolutionizing the systems and policies that impact sexually exploited youth." They work to both prevent exploitation, and help those who have been victims.
There are, of course, many more charities to work with. If everyone does just a little, it will make a big difference.