Tibet Permit requirements presently are that only groups of 5 people or more will be issued permits to enter Tibet. They must all be from the same country. This new rule while put in place this past year of 2012 may change in the future but for now that is what is required. You must supply a copy of your passport, along with your occupation, birth date and itinerary. Your travel service or tour operator will help you with this.
During the month of March in the past Tibet has been closed to all foreigners and we expect that to be the same again this year. If this changes I will post any new regulation or requirements on my blog as soon as they become available. Check my web site for tours of Tibet. www.interlakechinatours.com