Write Comics is great, FREE website that allows students to create their own comics.  This simple tool creates comic strips using different backgrounds, characters, and speech bubbles.  The nice thing about Write Comics is that there is no registering, students just start creating.  I found Write Comics really easy to use and really fun.  Since there is no registration you can only save your comic strip to the hard drive on the computer you are working on.  This may or may not be a limitation for your students.  I encourage you to check out Write Comics this year!