10 of the highest-rated apps for project management from the Google Apps Marketplace.
Gliffy
Gliffy is a Web-based tool that allows you to quickly create diagrams and turn complex information into easily understood images. Users are able to share diagrams or invite others to collaborate on one. The Revision Control feature automatically keeps a copy every time a document is saved, so you can track changes or revert to an earlier version. An extensive shape library is available to complement most any diagram.
Cost: Free 30-day trial / Free basic account / Subscriptions start at $4.95 per month per user