You can receive mail using i.Scribe using two methods. Manually by clicking receive mail on the toolbar or Mail | Receive mail. Or automatically by going into the options and on the POP3 tab setting he check every ?? minutes. This will go and check your POP3 account for email and download it periodically. New mail appears in the "Inbox" folder and a "New mail" icon appears in the system tray. Clicking on this icon opens the first new mail in the inbox folder.
To send mail using i.Scribe can be done from the mail message by clicking send, by clicking send on the toolbar or clicking Mail | Send Mail. Sending sends all unsent mail in the "Outbox" folder. Once a mail is sent successfully it is marked as sent and placed in the sent mail folder. To resend a mail, open it up and click "send" again. It's that simple (try doing that in Outlook).
The progress dialogs that send and receive use have a cancel button. This cancel is non-desructive, meaning that it doesn't break the current operation but waits for an appropriate moment to ask the process to stop. Currently that is only between mail messages. So the process will finish whatever it's doing (sending or receive a mail) before canceling the operation. The end result being that clicking cancel doesn't have any immediate effect but the process will stop at the next operation in the list. The progress dialog looks like this: