New BSC book due out for March/April 2010
http://www.amazon.com/Summer-Before-Babysitters-Club/dp/0545160936/ref=sr_1_2?ie=UTF8&s=books&qid=1251990038&sr=1-2
Scholastic has confirmed it (but they stated the release date as March 12, not April 1st like the amazon page says), and Raina Telgemeier who did the BSC Graphix has also confirmed it and said it was AMM's idea.