Applications :: Apple Mail 4.0 Slow To "send" Mail Using IMAP

i was using Apple mail 3.0 successfully on my old MBP which was running Leopard. I used POP to access and use my gmail account. I upgraded to a newer MBP but now am running snow leopard and apple mail 4.0 Unfortunately the migration assistant failed to bring across my data to the new computer and had to do it manually. I was unsuccessful in getting Mail 4.0 to set up a POP account for gmail as I had done with the older operating system's version of Mail.

I was successful with setting up IMAP (which i like less for specific reasons that I wont go into). However, even with following gmail's on line instructions, the sending of mails is temperamental. Sometimes emails get send, but almost always they sit in the "outbox" for minutes or hours, and it seems to be quite random as to when the emails are successfully sent. I cannot understand this. Usually the sending fails several times where it gives me the option to "try again" which I usually chose. I have SSL checked and am using port 933. I am using smpt.gmail.com:username@gmail.com has anybody else had similar difficulties and were they able to overcome them