I didn't answer it, but it's an out-of-state area code, so I decided to Google it. I assume it's probably some sort of telemarketing scheme, as I've received several phone calls from other out-of-state numbers that are just recordings (some of which are in Spanish).
Anyway, my advice? If you don't recognize the number, don't answer!
The people calling your cell phone are trying to monitor your phone conversations and steal your identity. Check out the payphone project in New York City.
These people are trying to access your cell phone signals and use your personal information. See the Payphone Project New York.
They are Mexicans or illegals looking for an identity and the government does nothing.
As it stands I was in a restaurant when I received this call 8/27/07 at 4:45 pm...I didn't answer it-especially since I am using PREPAID service through AT&T/Cingular....when I had a contract the "wrong" numbers I received such as this were far worse and my bill was always a horrible suprise....but still on a prepaid? Ridiculous.....although, I thought it was someone calling on my resume, it did make me check my email through my cell and I found out there had been someone contacting me via email to schedule an interview within minutes of this call (with an amazing co).! So annoying as it may have been, it assisted me in getting a call back to a potential employer! So its all their bad kharma!! ;)