If you receive a phone message from area codes 809, 284, or 876, with a request to call back, DO NOT CALL! Some people have been charged thousands of dollars when they returned the call. I just found this out, and it's verified by AT&T.
http://www.att.com/gen/press-room?pid=6045
"This long distance phone scam causes consumers to inadvertently incur high charges on their phone bills. Consumers usually receive a message telling them to call a phone number with an 809, 284 or 876 area code in order to collect a prize, find out information about a sick relative, etc. The caller assumes the number is a typical three-digit U.S. area code; however, the caller is actually connected to a phone number outside the United States, often in Canada or the Caribbean, and charged international call rates. Unfortunately, consumers don't find out that they have been charged higher international call rates until they receive their bill."