That’s really good from Miami at that time of year (around Christmas). I recommend you book it. I did a quick check with ITA and Kayak (see new user thread if not familiar with these), and next-cheapest is 803 (Air France), 839 (DL), 842 (LTU) and I would have suspected LTU cheaper, so I think you’ve got a good price. ITA and Kayak also found the 688.70 total fare with AA. Best, and cheapest, to book direct from the airline: www.aa.com — and be sure to sign up for their frequent flyer account if you don’t already have one; this trip should earn you nearly 10,000 miles.

Well the good news is that you should have a direct flight.  Often times around holidays the international leg isn’t very full, but the connection leg is and therefor price goes up.  But check the routes to make sure it is direct.  If it is, I think waiting until after laborday might bring the price down a little. 

Thanks for the great advice….we actually found a cheaper way to go by booking a flight thru AA from MIA to London Heathrow and coming home the same Madrid to MIA for $535 (all taxes included). Through the ITA website were able to find a BA flight from London to Munich for $112 (all taxes included) making our trip total $647 instead of $689….
 
However, when we call BA about the fare on ITA they say they have to charge $20 per person to do it over the phone…Is there any way to do it over the net using the ITA code?
 
Thanks again for any help.
 
Justin

Although you would have to transfer from Heathrow to Stansted, easyjet flies Stanstead to Munich.  Booking this far ahead you should be able to get it for $30 or $40, possibly cheaper. 
 
Just in case it works out here is some info on transport between the airports: http://www.londontoolkit.com/travel/interairporttransfers.htm 

ITA also found $86 for LCY (London City airport) to Munich, nonstop on Lufthansa. Here’s more from London-Munich in December: Skyscanner.

If you take Easyjet from Stansted, consider the cheap bus service: Easybus.

For Lufthansa from City, www.lufthansa.com
For BA from Heathrow, www.ba.com