Unwanted "announcement" on my MySpace Home page?

Yesterday I found an "anouncement" from someone named Tom about an online concert. "Tom" is not on any of my friend lists and I have tried to exclude any invitations from appearing on MySpace by using the privacy settings. Now, I cannot even get rid of this unsolicited and unwanted message. How can I keep anyone, including whoever the heck Tom is, from putting anything on my page and how do I get rid of this one?