If you configured Gmail access on your iPhone by tapping the large 'Gmail' icon in mail setup, please note that installing software update 1.1.3 will automatically convert Gmail on your iPhone from POP access to IMAP access. This means that actions you take on your iPhone will now sync with actions in your Gmail web interface (i.e. messages you read on your iPhone will show up as 'Read' in the web interface). This also means that messages you delete on your iPhone will be moved to the Trash folder in the Gmail web interface, and thus deleted after 30 days. Please exercise caution when deleting messages, as this behavior is markedly different from POP access.
For more information regarding IMAP, visit our IMAP Access topic.
For additional information regarding this change, please visit Apple Support.
If you wish to use Gmail IMAP access without deleting messages on your iPhone, please follow these instructions.
If you wish to continue using POP access on your iPhone, please follow these instructions to manually configure POP.