Britney Spears' younger sister Jamie Lynn Spears has announced in OK! Magazine that she is pregnant. Meanwhile her mom Lynne Spears' book on Christian parenting, due in Spring 2008, has been indefinitely delayed. Us Weekly reports Jamie Lynn's father - Lynne's ex-husband Jamie - is "furious" that mother and daughter sold their story to OK! and "devastated" at the news that his youngest child is pregnant. Jamie Lynn supposedly got...