Fotobabble
Fotobabble is both an iPad app and a web application. It allows you to take a photo, do some basic photo editing, and audio to it. When done, you can share it with others through email, social networks, link, or they provide embed code for your website. There are options to keep it private or make it public. The application is free. Here's a great video by a teacher that shows you how to use Fotobabble on the iPad and a web browser on a PC in your classroom.
Fotobabble - On the iPad from EdTechTeacher on Vimeo.