Small Photoshop script that shows a popup with a list of all the fonts (names and styles) used in a PSD file.
Copy this file to the Photoshop scripts folder and restart Photoshop
Example:
%ProgramFiles%\Adobe\Adobe Photoshop CS6 (64 Bit)\Presets\Scripts for the 64 bit Windows version
Installing the script in the Scripts folder will add a List Fonts entry to Photoshop's File > Scripts menu. You can use it by clicking on the new menu entry or by setting a keyboard shortcut from Edit > Keyboard Shortcuts...