If you install exchange 2003 on a windows2003 server, under the protocols tab of the server is IMAP4 (among others). This will have a little red x next to it, but right clicking on it gives you the option to start it. Pressing start means the mmc console will pause for about 1 minute and you then get "the service did not respond to the start or control request in a timely fashion. Check the Windows Event Viewer for details".
Checking the event viewer shows NO entries in the event log!
However, running services.msc and changing the Microsoft Exchange IMAP4 service from disabled to automatic and then starting it in the Exchange console results in a working IMAP4