Comics @ Mainada is probably the first web application in the world to allow users to draw complete comic strips directly online. It's free to everyone and can be a great showcast for humor sketch artists to show their art : you can draw online and immediately everyone else in the world with a net connection can see it.
ToonDoo is a cool, comic-creating tool. ToonDoo is a unique place for free and customizable online games of educational value for children of all abilities. You can now just drag-drop or click to create comic strips that express your views, opinions, angst or to just have fun.