This novella, The short second life of Bree Tanner tells the story of Bree Tanner, one of the newborn vampires from Eclipse. I wasn't sure at first if this was an April Fool joke (given when the news came out) but unless it's a very elaborate one, it's not.
Read more on Stephenie Meyer's official site (entry dated 30 March 2010 and also this page) which links to this site: http://www.breetanner.com/ WHERE YOU CAN READ IT FREE ONLINE FROM JUNE 7 TO JULY 5 2010 (tell your students!) .
There's a SMH article about it here and you can preorder it (if you want a bound version) at various places such as Better World Books (cheaper than Amazon, much cheaper overseas postage and profits to literacy). Looks like the Australian RRP is around $23.
Back at school and hitting the ground running.