Caveat: I've done some Perl and I've done some Windows but never Perl on Windows, so this is a bit hypothetical.

Under Win32, Perl can access any COM object through the Win32::OLE class. IIRC the correct class for Outlook is "Outlook.Application" However, you'll run into the problem you mentioned, which is that Outlook will not let you send email programmatically, regardless of language, without popping up a rather unpleasant confirmation message.

For receiving email, I don't recommend MAPI as it's ugly and complicated. You can use the CDO library through Win32::OLE, or, assuming your servers are Exchange 2000 or higher, you can access them with IMAP. Get the Mail::IMAPClient module from CPAN for this.

For sending email, I believe Net::SMTP is considered the canonical choice.