It is not known if all carriers are affected, however TMOBILE users are currently experiencing both Voice And Data failure as of this moment. 

T-Mobile Customer Initial Outage notification for NEW YORK NY

   Ticket Number: 548169
   Start Time: 09/02/08 12:38:12 PM (09/02/08 4:38:12 PM(GMT))
   End Time: TBD
   Service(s): Originating/Terminating Calls
   Description: Customer in the Manhattan, NY area may experience a degradation of voice and data services due to a fault on NYMSS913. Spatial Tier 2 is investigating the issue.
   Geographic Location(s): Manhattan, NY
   Status Update: Customer in the Manhattan, NY area may experience a degradation of voice and data services due to a fault on NYMSS913. Spatial Tier 2 is investigating the issue.
   Market(s): NEW YORK NY