If you are one of those who are planning for the exams by PMI, the 4 edition of the PMBOK is going to be out soon.
If you already have the 3 edition like me, theres a deadline to take the exam, unless you want to take the exam with the latest edition of the book.
PMP® Prior to 30 June 2009 PMBOK® Guide—Third Edition
PMP® After 30 June 2009 PMBOK® Guide—Fourth Edition
CAPM® Prior to 31 July 2009 PMBOK® Guide—Third Edition
CAPM® After 31 July 2009 PMBOK® Guide—Fourth Edition
To know more about the issue, you can click here .