This tutorial is for PSP 5; however, I have applied it to PSP 7 and 9. I've been told it's easy to adapt to PhotoShop also.
After you make the initial watermark, you will, essentially, copy and paste it over each photo. Once I made my watermark, I saved it in different sizes and to every main folder I have my photos in. That way, when I open the folder to grab the photo I want to edit or mark, I grab the watermark, too.
Here's the link:
http://www.grafx-design.com/24psp.html
Example of using this type of watermark:


