At Google I/O, during day 2's keynote, Google announced that Google documents (Google Drive), now support offline editing.
The docs will sync across all devices.
Clay Bavor, Director of Product Management for Google Apps demonstrated the feature on stage. He edited a doc, turned off wireless on his laptop, unplugged his ethernet cable, and kept editing like normal. All the formatting still worked.
Changes are saved locally to a local cache, he explained. "It just works," he said several times, sounding very familiar to Steve Jobs fans. "It just works works without you even noticing," he said.
He closed the document, and changes were saved. He plugged the ethernet back in, opened the doc back up in Google Drive, and it was synced again across all devices, in real time.
The feature is available today for docs. Bavor said they're working on this functionality for presentations and spreadsheets, and this will be coming soon.
He encouraged users to use Google Docs offline on their flights home from Google I/O.