Source code v2.1.7
QTads is included in Portage; simply emerge “games-engines/qtads”. If you're not on ~arch (aka “testing”), you might want to keyword it in your package.keywords to ensure that you get the latest version available. Sometimes Portage (even ~arch) does not offer the absolutely newest version though. In that case, an ebuild for the most recent version (including a live ebuild) can be found in the interactive-fiction overlay. It is accessible with the “layman” utility (app-portage/layman). If you don't already have layman installed, please read its documentation on how to configure your make.conf before adding overlays.
You should be able to find QTads on AUR. Another place of interest for Arch Linux users is ESCLINUX. Note that if you can't find a recent version of QTads in the above places, the binaries provided here should work on Arch without problems.
Recent versions are available in Backports media for Mandriva 2009.1, 2010.0 and 2010.1, and in regular media in future Mandriva releases and future Mageia releases. If the most current version of QTads happens to not be available there yet, the binaries provided here should work too. (Backports media are standard media in a Mandriva installation. If you're not sure what this is, you can find more information at wiki.mandriva.com.)
RPM packages for openSUSE can be found at the openSUSE Build Service.
Please note that when running on openSUSE, QTads does not support MP3 audio in games. This is a limitation of this Linux distribution. You might be able to work around this issue by installing SDL_mixer and SDL_sound from the Packman openSUSE repository (if they are available there.) For best media compatibility, however, it is recommended to use the binaries provided below.
Linux (32-bit and 64-bit) v2.1.7
The Linux binaries require that the Qt4-GUI and SDL runtime libraries are installed on the system. Please refer to the included README file for information about needed library dependencies.
Qt version 4.8 or newer is required for the binaries. If you want to use an older version of Qt, you need to build QTads from source code.
For correct MIDI support it is recommended to install the “eawpatches”; a complete GM-compatible MIDI sound set. You can find an easy to install package for Ubuntu at help.ubuntu.com. Note that QTads does not use Timidity, though a "timidify.cfg" file that points at the correct MIDI patches is still needed.
Mac DMG file v2.1.7
The Mac OS X application is self-contained and does not need any external runtime libraries.
Windows binary v2.1.7
Like the Mac OS X application, this is a self-contained application. Simply unzip and run it. Note that Windows XP hasn't been tested much, but it should work.