Migration from POP server to new machine

Hi,

I need to migrate a POP3 server to a new system running a different
MTA. Is there a program I can get anywhere that runs under Windows
and allows me to run it to collect mail from everyone's POP3 mailbox
on the old server, and send it out via SMTP to a set of specific
addresses, thus moving uncollected mail?

I could run this in a Batch file, for example, using the following
command lines:

movemail -popserver:10.1.1.2 -u:johnsmith -p:password
-smtpserver:10.1.1.4 a:john.smith@company.com

Any help gratefully received.
Thanks.
Andrew.