DiRT (Digital Research Tools) has a new home! Please visit Bamboo DiRT to explore this excellent collection of research tools.

Authoring involves the creation of interactive multimedia works.

Adobe Flash: "authoring environment for creating engaging interactive experiences" (Commercial, multi-platform)
Apture: can enrich a web site by embedding multimedia with a single line of code (Free, web-based)
Pachyderm: "Designed for people with little multimedia experience, Pachyderm is accessed through a web browser and is as easy to use as filling out a web form. Authors upload their own media (images, audio clips, and short video segments) and place them into pre-designed templates, which can play video and audio, link to other templates, zoom in on images, and more. Once the templates have been completed and linked together, the presentation is published and can then be downloaded and placed on the author’s website or on a CD or DVD ROM." (Free, but hosting is available; web-based)
Scratch: "Scratch is a new programming language that makes it easy to create your own interactive stories, animations, games, music, and art - and share your creations on the web." (Free, Windows, Mac, some Linux: works on the web)
Sophie: "software for writing and reading rich media documents in a networked environment" (Free, multi-platform)

Authoring Tools