qmail/MySQL - downloads
The latest release of the qmail patch is version 1.1.15.
If you are using netqmail get 1.1.15 for netqmail 1.05 (2006-03-29).
If you are using qmail get 1.1.15 for qmail 1.03 (2006-03-29).
These patches are functionally equivalent.
The latest release of the checkpassword patch is version 2.0.1.
Version 2.0.1 for checkpassword 0.90 (2001-07-26).
You do not need the checkpassword patch if you do not want to allow users to read their mail via POP (can also be used with Courier IMAP with some hacking).
Older releases (including the patch to checkpassword 0.81), third-party contributions and other miscellaneous stuff can be downloaded from the download directory. You will also find the unstable 1.2.x versions. Do not download these!
After downloading and applying the patch, you'll want to read the documentation on how to get set up your database.