|I would configure all of your devices to connect to the pop3 server and download email messages. In Outlook 2007 you have the option to "leave messages on server", "delete after x days", and "remove when deleted from 'Deleted Items' folder". You should have similar options on all devices.|
You can set the computer to leave the messages on server until removed from the Deleted Items folder, then set all other devices to never remove the messages from the server. I think that will do what you are looking for.
PS: You may also want to play with the "server timeouts" settings on each device. Some mail servers won't let more than one device connect to a single mailbox at the same time, and some servers/devices don't disconnect properly when they are done downloading mail. By making the timeout shorter (say one minute), you can force a disconnection after one minute of inactivity. That will reduce the likelihood of two people connecting at the same time from different devices.
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