I've found a few bits of heraldry software online that can be used to print out coats of arms. I thought these might be helpful to others so here they are:

http://web.meson.org/blazonserver/

http://inkwellideas.com/coat_of_arms/?page_id=8

http://www.puncher.co.uk/gen_herald.php

http://www.harnmaster.us/blazon.html (there's a link under the the word Blazon! at the bottom of the page that you might not otherwise see)

http://www.luz-herald.net/free/ (isn't software per se, but if you want to just copy somebody else's real heraldry it will do the trick)

Of all of the above I'd say Blazon!, not to be confused with Blazon (without the exclamation point), is by far the easiest to use due to its drag and drop interface,although the actual arms that it outputs don't always look the best.