We have access to the Book Citation Index as part of the Web of Science during a trial period until March 15th, 2013.
The Book Citation Index has a coverage of over 40,000 books and book chapters, starting with publication year 2005, but only 12% are from the subject area Physics/Chemistry (September 2012).
Jump directly to the Book Citation Index – Science: http://www.webofknowledge.com/?DestApp=WOS&editions=BSCI
or use the general Web of Science URL at http://www.db-hosts.mpg.de/WoS/.
Feedback is welcome!