How to remove a white background from a jpeg file?

Hello!  I am trying to remove the white bounding box/background from a jpeg logo file.  I have tried to remove it repeatedly using the Magic Wand masking tool and can get the mask set, but nothing happens when I delete (either using a right click or the delete key).  After deletion, I saved it as a bitmap thinking maybe it was transparent and I just couldn't tell, but when I import it into CD, it still has that white box around the logo.  HELP please!!!!

Thanks in advance for any help!