My htc Desire seems to send repeat copies of text messages that because of poor vodaphone reception do not get sent immediately.
Initially it notifies me that it could not send it and the triangle with exclamation mark running through it appears in notification.
From here the phone seems to do its own thing. There is no "outbox" so I cannot see the pending messages. If I query a message report it tells me if it has been received by the recipient or is in pending. Two more optional symbols appear on the texts

One is like a text speach box with a clock on it
the other is like a sealed envelope with an i in a circle on it.

What do these mean?

Why do the latter ones get re-sent at random times even if the notification says they have been sent and received by the recipient?
Why do the latter ones get re-sent sometimes more than once??