There is only 1 concert date set as of now, who knows there might be more concert dates if there is a high rising demand.
Ticketing Info
Ticket varies from US $44.50 - US $204.50 (including fees, it will be $59 - $227.9) and they will go on sale starting from September 9 at 10.00AM EDT via TicketMaster (Tickets are not available at the box office on the first day of the public on sale)
The concert will be held at the Madison Square Garden on October 23rd and it will start at 7PM.
Update 1
"The artists performing as part of SMTOWN LIVE are KANGTA, BoA, TVXQ, Super Junior, Girls' Generation, SHINee, and f(x).
The October 23, 2011 performance will go on sale Friday, September 9 at 10AM through http://www.livenation.com, http://www.ticketmaster.com, charge by phone 800.745.3000, and at selected Ticketmaster locations. If tickets remain, they will be available at the Madison Square Garden box office beginning Monday, Sept. 12."