You simply knit, or crochet, a square that is 8x8 inches, or 20x20 cm and post it to Africa. It will be sewned together with other squares into a blanket to keep an orphan or abondoned child warm. Two Australian families started this project a couple of years ago and now they have over 5.000 members in over 40 countries! Wow, that's amazing. I'm gonna be one of them! In 2009, 54.000 squares arrived to Africa and now in 2011, over 170.000 are made already!
If you rather knit a garment, there are instructions for you too, just visit their site, Knit-a-square.
No time to waste! Just start knitting!
And PS this is a GREAT project to introduce to your kids school, it is easy and the children will understand that they CAN make a difference and will raise awareness of this tragedy.