Yes great book, cant wait for the sequal to come out! Day by Day Armageddon: Beyond Exile (vol. II) is scheduled for mass release by Pocket Books in July 2010 Also I agree World War Z was also very good.
Follow his twitter account, link on his website. He's currently working on it as of today. He's at 25,000 to 30,000 words into it. And he's keeping his fans posted on the amount of words. His goal is 80,000-90,000 words. Exact date isn't set yet...probably late 2011 as it looks. Hope this helps. I can't wait!