This is our second attempt to migrate from Cyrus IMAP to Dovecot and now it is easy with a nice tool called imapsync
In order to compile it, you will probably have to install additional Perl packages both from Fedora native repositories and from Dries RPM Repository. The workstation where imapsync compiled successfully has the following Perl packages:
perl-5.8.8-4 perl-DBD-MySQL-3.0002-2.2.2 perl-Net-SSLeay-1.30-3.fc5 perl-DBI-1.50-2.2 perl-URI-1.35-2.2 perl-IO-Socket-SSL-0.97-1.fc5 perl-Cyrus-2.3.1-2.6.fc5 perl-Mail-IMAPClient-2.2.9-1.2.fc5.rf perl-TermReadKey-2.30-1.2.2