Miami is not freindly to cruisers who want to park their car. I found one lot near the airport that has cruise parking the cost includes a shuttle service to and from the port. Use UnitedAirportParking . com, the lot is called CBM you can completely prepay of just make a deposit. It definitely is not a fancy lot but it is much less expensive than the port.
Caribbean Trip Reports
Star Princess 2005, Sun Princess 2005
Caribbean Princess 2006, MSC Lirica 2006 , NCL Pearl 2007, Majesty of the Seas 2008, Carnival Destiny 2008, MSC Lirica 2009, Carnival Valor 2009,Carnival Legend 2010, Carnival Liberty 2010,Carnival Fantsay 2011,Carnival Valor Feb 2012, MSC Poesia Dec 2012, MSC Poesia April 2013, Carnival Legend Nov 2013, MSC DIVINA Jan 2014, MSC Divina Oct 2014