Ashlee Simpson, 23 and her rocker boyfriend, Pete Wentz, 28, are officially engaged, Usmagazine.com has confirmed.  Speculation about the quick engagement can only mean one thing - Ashlee is pregnant.Image details: OK! Magazine, Crush Management & Hilfiger Denim Host "Viva La Karaoke" served by picapp.com  No word on when the nuptials will take place, but if [...]