Missy
Two things you can do, use a WordArt box. Select the Insert WordArt button
on the drawing toolbar, choose one of the thumbnails in the last column all
relating to vertical text, select font and size, type your text and hit OK.
Or just choose the textbox icon on the drawing toolbar, click (don't drag)
on your slide, start typing one letter at a time and pressing enter after
each letter.
Does this help?