OS X equivalent of Windows keyboard commands to access in-application menus? In Windows, I often use the keyboard commands to navigate through the menus in a program.  For example, in Photoshop, I can do Alt+F, then D to quickly Save for Web &amp; Devices.  Or Alt+V, then D to Clear Guides.  This is great when there is no keyboard command for a menu item that I want to use, or the existing keyboard command requires too many fingers.  

How can I translate this functionality to OS X (OS X 10.5.8 in case it matters)?  How can I navigation through an applications's menus using keyboard commands?
You can use Ctrl + F2, which moves the focus to the  symbol in the menu bar. Then use the arrow keys to move around, or just type the start of a menu name to highlight it. With a menu name highlighted, hit Space to expand it. In an open menu, you can type the start of a menu item to highlight it. Once highlighted, press Space again to “click” it.

So, to get to “Save for Web &amp; Devices” in Photoshop, you could press Ctrl + F2, F, Space, Enter, S, ↓ until you focus “Save for Web &amp; Devices”, then Space.

Of course, the built-in keyboard shortcut for that option is much easier to type: ⌥ + ⇧ + ⌘ + S.