The file submission referenced in this post is no longer available on File Exchange.
I've long used SUPTITLE to add a single title across multiple subplots in a single figure. SUPTITLE is great for titles, but it doesn't do anything for labeling the x and y axes. Enter Ben Barrowes' convenient new submission SUPLABEL. SUPLABEL adds support for adding labels which span all subplots in your figure. Thanks, Ben.