Samsung will implement the use of the smart phone credential use to gain entry to the headquarters in South Korea in the second half of 2012 according to Daum.net.
Apple has not publicly released a NFC iPhone as of yet. Soon enough, I suppose.
In the United States, according to the Locksmith Ledger, Nokia, RIM and Samsung produce NFC smart phones.
I will report back if I get more information on smart phone and access control.