Leaderboard
726x90 pixels: Appears at the top of every page of the site
Medium Rectangle
300x250 pixels: Appears at the top of the right column on selected pages
Rectangle
180x250 pixels: Appears in the middle of the far right column on selected pages
Wide Skycraper
160x600 pixels: Appears in the middle of the far right column on selected pages
Full Banner
468 x 60 pixels: Appears below the main content on every page of the site.