Watermarking can be done fairly easy if you or your friend has photoshop.
Here is what you do.
Create an new folder where your watermarked images will be located at.
Open photoshop. If you are using Windows vista or later you need to run as administrator.
Open your actions palette (window > actions)
file > open > select image
In your actions palette click create new macro
Give it a name
Now create a new layer
Add your text or watermark symbol
set the opacity of the water mark
File > save as
select the new folder and name the file and everything else that needs to be set in the dialog box
close the image (but leave PS open)
Click Stop on the actions window. It is very important to stop the macro after you close the image.
Now you will have a macro that will create the watermark, save the image and close the image out. You may need to do one for each orientation, portrait and landscape depending on how you style the watermark.
Now what you need to do is create a droplet.
Click file > Automate > create droplet
In the save droplet location select the folder containing the to be watermarked images
Select the action you want it to perform. (This will be the action you just created. )
Make sure Suppress file open dialogs is checked
Set the save and file name options.
This will create the droplet .exe file.
Now that you have a droplet all you need to do is highlight all the images (or all the portrait/landscape image) and drag and drop them onto that .exe file. Then go watch some TV or get lunch and let the computer do the work.
The computer will then on it's own open the image, run that watermark action, close the image, and move on to the next image until it goes through all the images you selected. This is why it is important to close the image before stopping the macro recording. If that close command it not there and you drag 200 images onto that droplet photoshop will open them one by one and never close them.
It looks like alot but it is really simple to do. Once you know how to do these steps you can get this set up and running in about 2 minutes + the time it takes you to design your watermark.
Also, if you have trouble with the .exe file you may need to disable your anit-virus and firewall. I have norton and for some reason norton hates droplets and refuses to let it run.