[I've had a lot of great discussion in a previous thread here about my coat of arms designer. Several updates have been made since I last posted.]
The free, web-based Coat of Arms Visual Designer has been updated nearly every week with new features and more options for the past couple of months. Only a few things need to be added to consider it "beta" quality.
The software (which runs in your web browser) has many different uses, some for heraldry experts and some for people with a casual interest.
For a game setting, you may want to create a coat of arms for the key nobles in the game or maybe for each government and other key organizations. Players of knights or other noble characters may want to create that character's arms. Outside of gaming, you may want to create a personal coat of arms as an avatar for message boards or you may want to recreate an ancestor's coat of arms.
The Coat of Arms Visual Designer is available at http://www.inkwellideas.com/heraldry/
and the website includes a mini-wiki of heraldry information.
Since I last posted, over 30 new charges (eagles, bears, boars, other creatures, a few flowers, and a couple of other objects like an arrow) were added, users can now select the font of the optional name/motto scroll (using the "Tools" menu), users can set the borders of divisions and ordinaries, users can select the shape of the shield (also from the "Tools" menu), and more!