Popup Box Description OnMouseOver

I'm making a simple gallery space where the player can walk around and observe different works of art. My question is fairly simple (I've seen several solutions to this but haven't been successful in applying them to my scene just yet)

All I want to do is add a script to my collidable object that displays a pop-up box (possibly a graphic I design) when moused over and then disappears when the mouse exits, maybe even fade out. Even if it's just text I would like it to be black text on a rectangular white background.

Thank you for any help here I know it's probably a simple GUITexture scenario but I'm limited on time, and would rather have some input from someone who knows Unity's scripting language better than I :)