I just received a copy of Elizabeth Norton's Anne Boleyn – In Her Own Words & The Words of Those Who Knew Her.  It looks excellent – less a straight biography and more of a collection of primary and secondary sources such as Henry VIII's love letters, extracts from Cavendish's Life of Wolsey, George Wyatt's Life of Queen Anne, Chapuy's dispatches and Anne's own letters amongst others, some of which haven't been printed in decades.

I've only flicked through it so far and to read it cover-to-cover would certainly be a challenge but it it really looks like an amazing resource on Anne, especially if you were considering writing your own book!