I recently discovered a site, www.igive.com, where you link to online shopping sites and a portion of your purchase goes to the charity of your choice. There's a wide variety of merchants and a good selection of charities, and it's easy to use. There's also a mini-app you can download to let you know if a site you're shopping on is an igive sponsor so you can link through igive. Ue of the site is free with registration, and you can track money you've given through purchases. The only downside so far is that it appears you have to pick one and only one charity to support, so you can't give a percentage to a few different ones. They even give you the tax information necessary to take a deduction for the portion of your purchases going to charity.
My personal favorite charity is the African Wildlife Federation, so I use the African Wildlife Federation credit card so a percentage of all purchases goes to the charity. Then when I can use igive, another percentage goes their way. Of course, there is also a standard monthly donation going to them as well.
Although I've not used it yet, I also noticed the other day that Ebay let's you donate a portion of your sales income to a charity of your choice these days.
Last year's Valentine's Day post discussed other animal charities and habitat preservation charities, and ways to research charities you support.
No matter what your beliefs, hopefully you support at least one charity that is working to improve something you thing worthy of attention. It's always hard to go to Africa and see all that needs to be done, and come back here where people have so much, all the time.