According to the IBO website, the provisional dates for the May 2012 examinations have already been released. This are not the final dates, so they are still bound to change, but once the final schedule is released later this month I will change the title in order to post the dates for each exam. So far, IBO has stated that the provisional dates are the following:
2nd of May-22nd of May (regular IB exams)
30th of May (school-based syllabus examinations)