The Times Online reports that the Austrian government is sponsoring an art project featuring sexually explicit political posters: specifically, there's a to-do over a poster showing actors wearing masks of Bush, Queen Elizabeth, and Chirac having sex together (not work-safe). Best comment in that blog: "Wow! George Bush has a pretty nice body."
The other poster mentioned in that Times article is by an artist named Tanja Ostojic, apparently part of her political art project titled Looking for a Man with EU Passport. The image that's causing the kerfuffle shows a woman wearing blue underwear with the EU stars over her crotch (probably not work-safe).
Here's another image from that Ostojic project (not work-safe), though I don't think this one's part of the Austrian government-sponsored set; it's an interestingly disturbing mix of male and female.
(Update: Damn, BoingBoing beat me to it. See their entry for a little more info, including an update noting that the offending images are no longer displayed on the billboards.)