Omeka is a web publishing platform for sharing digital collections and creating media-rich online exhibits. A free trial plan is available at Omeka.net; see the left-hand navigation bar's section on Omeka for more detailed instructions.
Sample Omeka Projects:
Scalar is a free, open source authoring and publishing platform that’s designed to make it easy for authors to write long-form, media-rich, born-digital scholarship online. See About Scalar to begin.
Other free tools for exhibits include: