I wanted to report a blog being used for spamming. The URL is http://100percentpure.wordpress.com/. You can see an example of this spam at http://digg.com/users/anamika45 . I know this isn't exactly your problem, as the blog itself isn't spam, but it's being promoted everywhere as spam and I doubt that's what WordPress wants to be associated with.
There really should be a "Report abuse" link on WordPress.com; I can't report it there because the Contact form doesn't allow me to.