Open Cobalt is a 3D multimedia wiki environment designed to allow individuals and organisations to create collaborative workspaces and link together virtual worlds. Environments are enabled with voice and text chat, as well as web browsing and access to desktop applications. Useful for schools to set up 3D exciting environments for student classes or groups.
Glogster is a site that can be used to create online posters known as 'glogs'. Students combine text, images, video and audio into one interactive poster that can be shared online or integrated into a class blog or wiki. A great way of strengthing ICT skills whilst encouraging creativity. A basic educational account is free.
Wikispaces is a great tool to introduce students to creating and managing wikis using a simple WYSIWYG interface. You need to request a free educational wiki account directly, but this is worth doing as it ensures your wikis are private and ad-free.