This site: http://www.yvoschaap.com/wpthemegen/ has a simple free wordpress theme builder that anyone can use,
just update the settings via a nice form on the left side,
with the different options like background and sidebars settings,
you can choose if you want a right side bar,
how the left side bar should look, and you can choose which widgets to load to the left side bar.
After you have played with the main look you can generate the files and download a zip file which contains these files:
Or you can download each file seperatly.
This gives you the basic structure for a working wordpress theme, from here you only have left to customize as you wish.