Create a new logo - image on my web site

Please look at <[login to view URL]> site.I like to replace the top logo-image (replacing "[login to view URL]") to a beautoful moderate image. The image can be longer or shorter. Look at the content of my side. This site promotes Microsoft SharePoint technology and I like the logo matches with the content of the site. The audience of the site are IT professionals, IT Managers and or IT developers. I don't need to see resumes, or a lot of information from you. I am looking for some sample than can attract me. You are welcome to make a sample with water mark.