Collaboration

Apps

Craft is a meticulously-designed note-taking app for iPhone, iPad, Mac, Windows, and the web. It's well integrated with OmniFocus and is a great place for reference information and project support notes, whether you're using it individually or as part of a team.
Daylite by Marketcircle is a feature-rich CRM and business management app designed for individuals and organizations who have standardized on Apple technologies.
Evernote is a natural complement to OmniFocus. Use it to store ideas for upcoming projects and as a repository for project reference material.
A highly-flexible, cloud-based app that individuals and teams can use to write, plan, collaborate, and get organized.