Ok you need to add a new material, or you may already have one assigned by default, select your object then go to the shaders panel and then the materials subpanel (1st pic)
Then the alpha slider (2nd Pic)
Further to the right you should have a texture panel, add one (3rd pic)
Then you need to go to the texture buttons, and load your image (4th pic) Then back to the material panel you need to “map” the material to alpha.
Thanks for being polite (he called me sir :o) I am trying to be as well but it is frustrating when you have done as much research as I have to get asked such a basic question. There is this thing called the wiki…you know? Seriously though here are some links.
The best material tut I know of ^^
The wiki: http://wiki.blender.org/index.php/Doc:Manual
For fun as you are now officially a member of the cult of the noob.
Good Luck and happy blending
P.S. All the buttons will make your head swim, and it seems as if they are unneccessarily complicated, but there is a method to the madness and puching through it all is very, very rewarding…maybe one day you will become a master and help me.