Batch resize images with imagemagick (convert)

I am often asked how to resize a directory full of images, for free. This is definitely possible and probable there are many ways to do it, but I like to use ImageMagick for this. ImageMagick is available for almost any OS here:

http://www.imagemagick.org/script/index.php

Here is an example of converting a directory of JPEGs using a little scripting and imagemagick:

for i in $( ls *.jpg); do convert $i -resize 1024x768 sm_$i; done;