Vector vs. Raster (Bitmap) Graphics

As a software engineer I never really had the inclination (or need) to learn much about design and graphics. Until I decided to start developing iPhone applications and wanted to create my own graphics to set my apps apart. I kept bumping into references about vector objects and graphics and I had no idea what they were. Until I finally stopped being lazy and looked it up. :) So here it is in plain and simple terms:
A vector graphic differs from a raster image(or bitmap) in that, the former does not store its pixel information, but rather it stores information about how to draw the image (line, curves, points, etc.) after it it applied to a mathematical formula. This allows you to re-size, re-color, deform, as well as many of other things to the vector graphic, without sacrificing the image quality. You can read more on vector graphics here.