Yippee!  You're buying a new home!

IF YOU'RE A GOOD SPY, YOU CAN DISCOVER
 A REALLY HELPFUL MOVING 
TIP FOR YOU AND YOUR FAMILY~!

When spys need to send messages, they often time use one letter to mean another.
  To figure out what this important sentence says, you need to figure out 
what the code is.  Some have been done for you to help you out a bit, but even
with the hints, this one is REALLY hard.  Good Luck!