Can You Break Codes?

The Federal Bureau of Investigation employs a crack team of cryptanalysts to break ciphers that criminals use.  Some ciphers are simple, such as the codes that numbers runners and other bookies use for illegal gambling.  Others are a bit tougher, such as codes used between gangsters in prison and their organized crime families still on the outside. 

But rather than giving the cryptanalysts a cipher to break, they have created one for the public to play with.  The FBI has posted the crypto puzzle below on their website.  Anyone here game enough to try to crack it?  Feel free to post clues in the comments section.

PIKODENHFENJIKM! YIH QELB GDISBK NQB PICB. OI NI AGJ. OIL/PICB.QNT MI WB SKIW, EKC UFBEMB PIKMJCBD E PEDBBD WJNQ NQB AGJ.

Hint: if you want a primer on basic cipher systems and how to break them, see the article Analysis of Criminal Codes and Ciphers.

One of the most famous cases where FBI cryptanalysts were used was the Zodiac Killer case.  The FBI has a page on that here.