These days when he isn't rocking out with Fall Out Boy, Pete Wentz can often be found speaking to his unborn child or reading books about fatherhood. "I talk to it all the time," he told PEOPLE Saturday at the Ultimate Fighting Championship 86 afterparty in Las Vegas. "The Expectant Father tells you that the woman, when she speaks, the baby hears her all the time. And the father's voice isn't familiar unless you talk to it, so I talk to it all the time." Armin Brott's parenthood tome is just one of the books the bassist is reading to prepare himself for his and Ashlee Simpson-Wentz's first child together. "It tells you your partner's moods month-by-month and week-by-week," says Wentz, who is also getting advice from both his father and Joe Simpson. "It tells you why you're feeling the way you are, how you can feel more involved in the pregnancy." And while Ashlee often has cravings for ice cream, pickles and green olives, everything is "going well," says Wentz, who performed a two-hour DJ set at the House of Blues following the UFC match. In fact, he is already hinting at more children in the future: "This is the first one so we'll have to base the next one on how we do on the first one." http://www.people.com/people/article/0,,20210586,00.html