Cost: The app is free. Pricing for the online tool starts at $15.95/month.
Available on Android too? No, but an Android version is in the works.
Smartsheet is an online project management/collaboration tool. With Smartsheet, you see an Excel-style interface that lets you invite collaborators, set controls, keep track of versions, set alarms, etc. The mobile app lets users access any project from an iPhone or iPad, and it keeps everything in sync and up to date.