Wai, I try to help abit:
> Open up Actions Palette > Click the top right Circular button with an arrowhead pointing right
> Define Actions > Enter a name > Enter a shortcut key if u will (eg, Shift F2) > Open your image
> Press Record on the Actions Palette. Action Palette will now record your instructions.
> Click on Marquee tool > Under Properties Bar, Define Fixed Size
> Set 300 for x and 300 for y
> Click on your image, you'll see your selection Box. Notice in your actions palette, the exact coordinates and dimensions of your selection box is captured.
If you wish to manually defined where to crop, press STOP on the actions palette here. Now whenever you PLAY this action on any image, the exact coordinations and size of selection will be shown.
If you wish to automate the cropping process, just carry on further, DUN press STOP.
> Menu-Image-Crop. Your image is now cropped. > File-Open-Save As. > Save your file with BMP format in any folder. Photoshop will remember the format and settings, not the names.
> Close this File. Notice the action is also recorded.
> Press STOP to stop recording.
There you had your actions recorded.
How to apply to a folder?
> File-Automate-Batch
I think the dialogs are pretty self explanatory, basically it's to apply the actions to an entire folder.
For automated cropping, you must select using the marquee tool and then choose Image-Crop from the menu. You cannot do automated with the Crop tool.
Well, actually you can.. drag guides to location, set snap to guides, drag a crop area defined by the guides, and doubleclick to crop.. just get-arounds.