You can find how to apply to this and other positions on this UNESCO website.
I have noticed that postings relating to employment at UNESCO continue to receive many visitors. If you are starting the process of getting such a job yu may find the following interesting:
- "Getting a Job with UNESCO", Americans for UNESCO website
- "Getting a Job with UNESCO", Blog posting
- "Jobs at UNESCO", Blog posting
- "Americans Still Underrepresented on UNESCO Staff", Blog posting
- "Editorial: How Young Should a Young Professional Be", Blog posting
State Department's U.N. Jobs website