Windows/Mac/Linux: The free Adobe Shortcut App gives fast access to look up keyboard shortcuts for the entire array of Adobe products from one simple place.
Once you've installed the Adobe AIR application, you can choose a program from the buttons on the top, and find a shortcut using the search box, browsing or even adding them to a favourites list. You can switch between viewing Windows or Mac shortcuts, or even view the cheat sheet in PDF format. It's a quick and easy way to look up the shortcuts without having to pull out the help file. Adobe Shortcut App is a free download for all platforms, requires Adobe AIR.