Just to clarify, currently, documents created on Pages, Numbers, or Keynote for iOS, and where in Settings->iCloud->Documents & Data is in the On position, will be visible on iCloud.com and other iOS 5.x devices with the same iCloud account. Documents created on Pages, Numbers, Keynote for Mac OS have to be synced through iTunes File Sharing or uploaded to iCloud.com to be visible on an iOS 5.x device.
When Mountain Lion is released this summer, the Documents in the Cloud functionality should greatly simply things.