I can never recall the fancy words the heralds use in their descriptives. The sites below use at least mostly plain English, and I have found them helpful. They are here partly because I don't want to lose the links!
SCA Heraldry Wiki - This links to the Pennsic Traceable Art page, but the entire site is useful.
SCA College of Arms
Wiki: Attitude: Heraldry - good, simple, illustrated 'this is how they are standing' page.
Pictorial Dictionary of Heraldry - basic information and drawings. Good to start with, and a VERY helpful site overall for me.
SCA Armorial Search page - covers the Knowne World. All words, no pictures. Know your herald-ese or have translations handy =)
A Complete Guide To Heraldry - by Arthur Charles Fox-Davies, in Edinburgh, 1909. Now in public domain. Has the illustrations, too.
