Do you want to create your own WordPress template? It is not hard actually if you have enough knowledge of XHTML (or HTML) and CSS, and a little basic of PHP. This guide will split into multiple part as it is quite long. This is my way of creating WordPress template, so it might different than you. The first part is for preparation and designing, I haven’t touch the coding part yet, it will be on second part. I will make it with example and this example will be available to download for everyone later. Hehe… 
First is the preparation. For me, I will take a paper and a pen and start thinking of how the template will look like. Hmm… As of now, I will create a simple templates like usual blog template. One header with logo and description on top, one sidebar on left side, the content is on the center (right side from the sidebar), and one footer on bottom. That’s it. Okay, once you are ready then, let’s open your favorite graphics editor. For me, it is GIMP.