@CitizenCL more than one type of visa is available, the only way i know that the organizers can set this up is by getting Asiana airlines or one of the big sponsors of the event to back them into getting either a tourist-visa, business-visa or temporary worker visa. It will involve embassy services but not immigration, i doubt the girls are applying for immigrant visa's which would allow them to immigrate and acquire US citizenship.... plus it takes a year and petitioning.
the odd part about this story is if you check http://www.apeconcer...07.cfm?cID=3245 , the venue's event page for t-ara, the cause for postponement says "due to an injury", meaning Eunjung. it struck me that they'd use two stories. are fans that mad? idk. i can wait til april. Core Contents Media hwaiting!!!