There is a lot on the web that website offer free download template that you can use for your theme, which is for google adsense, wordpress theme, blogspot. Many kind of color, background picture, number of column and more features.
maybe basicly before you edit your own template you have to know a little about html, so you can edit and make your own design, just for example this is preview of my template
For my advice, before you edit your own template, you should save it on your hard disk for our back up if there is something wrong when you edit your template. There is much tutorial you can find on other blog or wordpress just searching for it.....
If you interest of my design template you can download here [leave comment if you interest, or message on shout box, I'm not uploaded yet]
Leave a comment if you have trouble to apply my theme on your blog[blogspot.com ONLY]
P.S: my blog template is all ready include read more……., bookmark to a lot search engine like: Digg.org, Yahoo, google, Esnips, etc, emotion character include :)