Like I said before, I’m not that great of an artist; but I can kinda draw. And as Stu says in The Guide, that’s all you need.
I had a Wacom Tablet from a few years back and literally pulled it out of the attic, made a Photoshop file with a bunch of 2.39:1 boxes. I basically read through each section of the script, let it play out in my head and then I jotted it down in the form of stick figures filling over the boxes on layer above them. Then, when the section of the story was concluded, I went back and filled in the drawings a little more. I know that this step was a bit anal, and overall unnecessary-but I did it anyway. Plus, it was cool seeing this story come to life in the form of little boxes on my computer screen. Even cooler when I printed them off. ;)
I just wanted to say again that you don't need Photoshop, or a tablet to do storyboards. Just grab a pencil and a piece of paper. And start doodling. If you are just terrible draw stick figures. Also, this is a great place in the independent film making process to start to use some of those people around you who can do this type of stuff. Do you have a friend whose an aspiring artist? Well, see if they'd be interested in fleshing out your stick figures.
One last thing, if you don't have Photoshop but would like to to work in that format, get GIMP. It's super cool. And free. :)