I'm trying to add a watermark to the bottom of a video with my site URL in it for YouTube like you can see what I mean on this video:
YouTube - Sex and the City Movie Official Full Length Trailer

I am on a mac and I have quicktime pro, imovie, photoshop, etc. I've searched google for a number of things and tried different options but nothing really works. Any help would be greatly appreciated!

This?

I don't have a mac so I've no idea if that works.

thanks - i had actually seen that when i googled and i could not seem to make it work. i tried a few times and each time it did not work.

Every other tutorial I've seen on a mac does it exactly the same way, or some variation thereof.

There's millions of ways to do it on a PC
(not helping I know, but ....)

i feel like a retard. i should be able to do this!

How exactly is it not working??