Opposable Thumbs: Using Procmail and IMAP.

robin whittle: Postfix, Courier Maildrop and Courier IMAP.

Mb2md is a tool for Converting Mbox mailboxes to Maildir format.

...and an important note for everyone using courier-imap, maildir and apple's mail app: don't use Maildir/ as imap prefix, simply use INBOX.