ToonDoo is service that let you create comic strips easily. If you not able to draw cartoons yourself and want to show your creativity to the world this is a good place to start.
Once logged in you can start creating cartoons, first select the your preferred layout, 3 layouts are available at present one panel, two panel and three panel.
Use the character buttons above the working dashboard to select your funny character, when you click on a character it will show you the characters in different moods, drag and drop the character to your dashboard. Now you can add text, shapes, backgrounds needed to create your cartoon.
Once you are done with your you can save that comic or share with your friends or make it private. You can also embed these comic strips on your blog or myspace or facebook profile.
Overall the site is good, it is built on flash platform. There is no learning curve involved, you can start creating comics by drag and drop. There are some features which are missing like ability to customize the text color, and ability to change the character looks (clothing etc). If you have some spare time give it a try and create your comic strips.