No probs - there are probably better described versions than this but here goes:
First open a 'sample photo' could be anything but make sure it's not important so you can mess around with it. It also needs to be a standard size so 600x400 for example if that's the size you post onto the web.
In CS4 make sure your actions palette is open - if not select from 'window' in the menu bar. At the bottom of the palette click the small folder to set up a new action set. Let's call it 'signature' for example.
Then click on the small square with the turned up corner just to the right of the folder. This will set up a new action. Name your action something like 'Horiz' (if it's for horizontal/landscape photos) and select the set as 'signature'. Assign a function key if you wish but it's not essential.
You now need to record your action. Click on the small circle to the left of the folder icon. Anything you do now will be recorded. Put your signature on the photo doing whetever it is you have to do. When you are done, sharpen the image if necessary, then flatten, then close and save (presumably jpeg at whatever compression you like).
Finally stop the action from recording by pressing the square at the bottom of the action pallete. That's it, you're done.
Repeat the above for your virtical (portrait) photos.
To run the action on a number of images then select 'automate->batch' from the file menu. Select the set 'signature' and the action 'horiz'. Set source to folder and choose the folder where all your horizontal 600x400 images are stored. Not sure if you need to set the destination but it should say save and close. However, we recorded the save and close as part of the action so tick the box that says 'Override Action "Save As" Commands'. It'll display a warning message but that's OK, that's what we want to do. The reason behind this is that whenever I have not included save as within the action it asks me every photo for the compression level - on 400 photos from a wedding it's really a PITA so better to have it in the action.
Just to be on the safe side, when I edit wedding photos for web (or DVD) I export them all into a new folder at the required size from lightroom. Then I copy all the horizontal photos into a sub folder called 'Horiz' and all virtical photos into another sub-folder called 'virt'. This makes sure that if something does go wrong I have other copies of them and it also means the 'horizontal' signature action doesn't affect the virtical ones and vice-versa. I then run the actions on the separate folders. When I'm happy they are all done I copy them back to the top folder and delete the sub-folders. The names should remain the same so they will sort back into order.
Disclaimer - I have to go to a meeting and haven't had time to sense check it so I'll have a look later tonight. There may be better ways to do this but it works for me. Hope it's helpful.
