Adobe Illustrator has an awesome tool that I’m willing to bet most designers have never used. The Width Tool.
The Width Tool (pictured at right) allows you to adjust the width of paths—not just the entire path as a whole, but the parts of the path between handles independently (see the image above for examples normal paths, and the same path adjusted with the Width Tool). Adjustments can be made to any path, including outlined fonts.
For the full scoop check out Getting a Handle on Illustrator’s Width Tool over at Creative Pro