I just finished reading Roger C. Parker's latest book, "Design to Sell." Roger is a well-known marketing expert who teaches 'non-designers' how to create well-designed marketing pieces. The reason I enjoy reading Roger's work is that all of his blogs, books, newsletters, etc. are an example of how great design can enhance the reader's understanding of the material. You can download two free chapters of the book and signup for his Design to Sell Newsletter. It's well worth your time.
'Design to Sell' talks about using Microsoft Publisher to plan, write and design memorable marketing pieces. There's lots of great information about planning and crafting messages as well.
Anyone who reads this blog regularly knows that I consider design an integral part of marketing. Companies like Target have grown exponentially, because they understand that good design doesn't have to cost more. The key is that you have to give it the time and attention it requires. If you do, you'll have a competitive edge.