You will need two components for the Cyrus IMAP server, the server cyrus-imap and the SASL libraries for authentication. The Cyrus project's home page is http://asg.web.cmu.edu/cyrus/. From this page you can obtain the latest compressed tar files for the imap server and the SASL libraries. Alternatively and more convenient, RPMs are available. As of this writing, cyrus-imapd-1.6.1-2.i386.rpm and cyrus-sasl-1.5.3-2.i386.rpm are the latest Red Hat RPMs available from http://www.rpmfind.net. There are libc6 contributed rpms available at this location that are more recent. The latest rpm releases are cyrus-imapd-1.6.13-1.i386.rpm and cyrus-sasl-1.5.5-1.i386.rpm