I would like to learn how to make my own Wordpress themes but honestly do not have a clue on how to begin. Does anyone know of any place where they tell you how to do this or offer tutorials? I am working on several blogs currently and would like to come up with unique designs that are not already all over the web.

There are several open source template sites out there. If you know HTML/CSS find one and start mucking around in the guts of the template. Lots of blog themes are CSS based these days which makes it easy to find and replace elements until you've created your own custom theme. And with open source you can do this without remorse or worry about copyright infringements.

I can do the basics of HTML if I don't try to get too fancy yet but I know absolutely nothing about CSS. I suppose with an open source template, I could easily experiment on my desktop before trying anything actually online. That's how I played with HTML and didn't try any actual work on a website until I was more comfortable with it.

I know you can find open source design at oswd.org but for some reason, I hadn't thought to actually play around with the designs. Thanks for the lightbulb moment.

I would start by taking a default theme and editing it first.