Present.me takes slide presentations from a variety of formats and then converts them so that you can record audio and then share via the cloud. It does work on mobile devices.
3DTOAD.com is a library of 3D images that you can rotate and explore. It includes skulls, skeletons, dissections, coral, geology, and even music. These could be great visuals on an Interactive White Board or used on an iPad.
We use VoiceThread in a lot of our EdTechTeacher workshops as it is completely web based and now includes an iPad app. As a tool, it can create digital stories, be used for foreign language exercises, or support the creation of collaborative study aids. This library is a database of articles about successful VoiceThread projects.
Through this Java Applet, it is now possible to share your screen with any computer or device. It could be incredibly useful for demonstrating a technique in a 1:1 setting.
Unlike other social bookmarking sites, Pearltrees gives you a visual way to see and share your bookmarks. It also helps to consolidate bookmarks between devices.
The lite, free, version of this web service lets you create presentations and import them from either PowerPoint or Google Docs. There is also an iPad/iPhone app.