Most organisations will start to advertise their available PhD projects for 2009 around the end of July 2008 / beginning of August. Some will advertise as late as September. Generally closing dates for PhD applications will be towards the end of October.
However, although the above holds true in many cases, universities and institutes are continually advertising throughout the year and just because a deadline to get applications in by may be stated in the listing, it doesn’t mean the position will be filled. It is sometimes therefore worth enquiring with the organisation to check the position has been filled after the application closing date if you are keen, in case it is still available. Even if it is not, they might have something similar in the pipeline to tell you about.