So now we know, it was indeed a shotgun wedding for Ashlee and Pete.  Pete released a statement on his website, friendsorenemies.com stating, "While many have speculated about this, we wanted to wait until after the first trimester to officially confirm that we are expecting our first child.  This is truly the most joyous time in our lives and we are excited to share the happy news and start our family." 
I wonder if their baby is going to be born with really flat bangs and tons of eyeliner...