A word of caution since you're excited (as I was):
If you want to get it done, be there when they open or plan on circling back by there periodically throughout the day to see if the line is short. We had planned to have DS2's (then 11 months) first cut there when we went in September 2008 (a very unbusy time), but we got to the barber shop at 10 minutes after opening and found a line about 10 people deep. The line was about half kids and half adults getting the spackle and glitter treatment. We waited for about half an hour and moved up about four feet, so we gave up. Rather than waste park time, we just waited until we got back home. If I had it to do over again, I'd be first in line at rope drop and bee-line it to the barber shop!