suplabel
this is one that i downloaded from matlab central file exchange: suplabel, places one x or y axis label on a bunch of subplots. Because sometimes redundancy is bad.
http://www.mathworks.com/matlabcentral/fileexchange/7772-suplabel
I changed the default supAxes to [.12 .12 .85 .85 ] so they wouldn't be chopped off. Download it to your path and off you go.
Places text as a title, xlabel, or