I've recently begun designing my own WordPress theme. The last time I really worked with any sort of web "design" (I'm using that word rather loosely here), layout was done via tables instead of divs. Stephen at Acadian Imaging told me that in order to get my theme to work the way I wanted with divs, I needed floats. Root beer floats are delicious, but this is not what he meant apparently.
Now it's time to give credit where credit is due. When it came to floats, I was completely lost until I came across Floatutorial by Australian-based Max Design. When they say "simple tutorials on CSS floats", they aren't kidding. These tutorials are simple enough for even a complete novice to understand. Within a few minutes, I was able to get the exact layout I was looking for thanks to these step-by-step guides.