I'm always on the look out for interesting web-based applications, and when Bob W. from my district sent out a link to aviary.com I was quick to take a look. This site offers a complete suite of graphic editing software (image, effects, colour, vector): it's really quite amazing. I was really taken with the audio editor Myna (...everything is named after birds!) and found it to be remarkably like Garage Band. The layout and controls will seem very familiar to Apple users. For kids who are turned on by music editing, this is a great free app. (One caveat with this site is that you are able to see and hear other users' image and audio creations. Depending on the age level of your students, it might be problematic.)
There are great demo videos that show the power of these applications. Here's a teaser:
