Welcome to our world ! I'm quite new too, so seeing another "rookie" coming is always nice !
If I had to chose one advice it would be this one :
If you get the last edition of the book (2007 and after), most of the updates are in it. Anyway, a look at the book amendment section is always good (helped me a lot !) :
http://www.haynes.co.uk/forums/showthread.php?t=2430
If you get a second hand book edited before 2007, the amendment section is then more than recommended !
Enjoy !