Who is this. Received 4 call today from this number.  3 within 3-4 minutes apart.  Call back gives recording saying, "call cannot be completed as dialed"

I received a call from them at 9:11 AM Tuesday 18 November 2008.  It was apparent that they were unaware the phone had dialed my number as it sounded like they were in transit in a vehicle.  The call lasted for 35 seconds of background noise.

I had a missed call from this number, which coincided with a voicemail from a friend staying at a hotel in Miami.  Possibly some type of local relay number for AT&T for out of area calls?