Spam Inserted in Header on front page

Hi, some spam has somehow gotten into the header of my start page.
How do I get rid of this?

You can see a screen shot here:
http://charliecheney.com/images/GoogleChromeScreenSnapz002.jpg

It says: "Roaccutan by Roche is use in europe buy isotretinoin during pregnancy and lactation using"

This text us below the Site Name and Slogan, but above the menus.
I'm using Acquia Marina theme 6.x-2.0 and Drupal core 6.22

Thanks in advance. -Charlie