I just installed this plugin, and it allowed me to remove the links to the theme creator in my footer. Considering that I actually paid money for the theme, I really don't think I need to link to them on every page of my site! Besides, it seems less professional to have the theme links, and there may be security advantages to obscure the theme and wp versions you use.
I am a technical user, but I'd rather not hack source code if I don't have to. This plugin does the job nicely.