This program plays games and provides game analysis. Download it here.
Words With Friends
Available through Facebook and as an app download for mobile on Android and Apple devices.
Word checking and judging programs
A word study program written by Michael Thelen and modified by Collins. It's free. It can be used as a Word Judge for tournaments and also for word study. It does not provide a facility for playing games. You can add the CSW15 word list to it separately. Download it here.
A word checking and judging program for mobile devices. Free to download and use. Instructions for downloading and setting up here (thanks to Dylan Early). Note that the URL in step 6 is case sensitive.
A programme for creating draws and scoring for tournaments. It's a DOS programme so to run under windows you will probably need to use Dosbox. See the operating instructions for details. Download it here.