Angels & Demons by Dan Brown.
You guessed it right, from the stables of author of 'Da Vinci Code', just that, it was published before 'Da V...'
Apparently, after his phenomenal success with 'Da V...' readers started digging up his previous works and Angels & Demons started selling hotcakes once again ! and no, i did not do the same ;) ;p
So far this book has had an identical opening. The main character/hero is still Robert Langdon... the way he gets pulled into an 'International Mystery' once again involving religion, mysterious secret groups & codes are very xeroxically (tried coining that word now) similar to 'Da V...'
Keep watching - will follow up with a review.