For the duration of its existence until now, the offline experience on Gmail.com from your iPhone or Android phone has been a unidirectional activity: you could compose outgoing mail, but not view it before it sent.
No longer. Introduced on Thursday, Outbox is a new Gmail.com feature for Android and iPhone users. It provides mobile Web users a way to view the queue of outgoing messages that Google will ship out once the cell phone gets back into a coverage zone.
We tested Outbox by opening Gmail from the browser and then switching the phone to airplane mode. When you create a message and send it, you still receive Google's confirmation message that the e-mail "sent." But arrow back to the Gmail menu and you'll now see a label for Outbox that appears below the Chats label. Tap it to view the subject line, time stamp, and first line of the e-mail you have waiting for delivery.
Since Outbox is a limited read-only feature, you won't be able to edit the e-mail, or even tap it to read the entire body. However, it does provide an at-a-glance confirmation that an e-mail is still waiting to be sent.
Gmail.com for mobile is accessed from the browser on iPhones running 2.2.1 of the operating system or above, and on Android phones. It's available in U.S. English.