iPad/iPhone 4/iOS 4: Send & receive attachments using the device's built-in Mail app
iPhone/iPod touch WITHOUT iOS 4: Send & receive attachments in MS Exchange & Gmail
Access, use & sync files stored in Google Docs, Dropbox, Box.net, iDisk & SugarSync
Includes desktop app (Win & Mac) with 2-way file sync (Wi-Fi required)
IPAD, IPHONE 4, IOS 4 SPECIFIC FEATURES
Open & edit files directly in DocsToGo from any third party app that supports the "Open In…" file sharing feature. (E.g. the device's built-in Mail app can now open supported attachments in Docs To Go)
Supports iTunes File Sharing via USB cable for moving files between your device & computer