QControl - A replacement for Vqadmin - a free version is available, as well as a commercial version.
VCGSend - A web app that allows you to send large files without using email attachments or FTP. Stop bogging down your mail server! More info and purchasing is available here.
QMT-ISO - An ISO installer for CentOS with Qmailtoaster - have a working mail server in about 30 minutes.
QmailToaster Virtual Machine - Run QmailToaster in the free VMware Player.