This is the easieast tool I've seen to create comic strips. I've been planning to create a comic strip with my students in class and then ask them to create mini dialogues with language learned that day for their own comic strips. http://writecomics.com/
You don't even need an account. First you click on the characters, then the backgroun, choose a speech bubble, type in the text (click SUBMIT WORD) and when you've finished click FINISHED and you've provided with a link. It's that easy.
:( It's a pity they don't offer us an embed but you can always grab a screenshot and publish it.
These are some comic strips created by a colleague of mine, Angela Gonçalves, to present modals of deduction.