Preceden - Preceden makes it easy to build simple, powerful timelines
StoryMill - Developers and publishers of Mac, Win, and iOS productivity, home and office and writing software such as MacGourmet, Paperless and many more. Based in MN.
Timeline - Timeline is a cross-platform application for displaying and navigating events on a timeline.
Novelize - Novelize is an online novel writing app designed to keep authors on track.
Tiki-Toki - Tiki-Toki is web-based timeline software for creating beautiful interactive timelines that you can share on the web.
Manuskript - Open-source tool for writers.