Pixton – Has an educational portal (paid) that is ideal for schools (no student email account necessary). Also, there are a ton of options such as voice recording, drag-n-drop interface, and importing/exporting features.
ToonDoo Spaces – One of the most popular online comic creators that is very similar to Pixton, with the ability to create a private space for education for sharing/collaborating on comics.
Comic Master – A very nice-looking site that is user friendly with lots of features to choose from such as: backgrounds, objects, speech bubbles, etc.
Bitstrips - A great site with an educational instance (paid) that allows students to create comics in a safe/secure environment.
Stage’D – A great-looking site for creating animated comics!
Make Beliefs Comix – A wonderful site with lots of options to choose from — it even lets users create comics in Spanish.
Super Hero Squad Show – A fun site for kids to make comics off of their favorite Marvel super hero.
Chogger – A nice site for creating a comic, with the ability to create a drawing from scratch.
Comic Creator – From Read Write & Type, a easy/simple to use comic creator that is nice to use with the younger kids.
Witty Comics – A comic creation site that focuses more on creating text more then anything else.