I've had some visitors ask me if I would do a tutorial on how I made my banner for my blog, when in reality I myself found a tutorial that guided me through it. lol First I checked out Picnik. It's a web site for photo editing and lots of fun stuff. I've seen it on other blogs for projects, so I decided to purchase the premium version. I see a bunch of projects in my future on this site. Next I went to this tutorial at The Mother Huddle (which is a fantastic blog). It guided me right though it.
Then I went a little crazy with it and made a signature and a Favicon (that little box next to the address).
Hope this helps,