Give this a shot:
DECLARE @table TABLE (Date VARCHAR(6), TotalUnitsAvail INT, RentedDuringMonth INT, VacatedDuringMonth INT, NetRentals INT)
INSERT INTO @table (Date, TotalUnitsAvail, RentedDuringMonth, VacatedDuringMonth, NetRentals) VALUES
('Jan-13', 60, 17, 11, 6 ),
('Feb-13', 60, 11, 6, 5 ),
('Mar-13', 60, 19, 14, 5 ),
('Apr-13', 59, 14, 13, 1 ),
('May-13', 60, 11, 16, -5),
('Jun-13', 60, 16, 17, -1),
('Jul-13', 60, 14, 14, 0 )
;WITH tua AS (
SELECT tuay, 
MAX([Jan-13]) AS [Jan-13],MAX([Feb-13]) AS [Feb-13],MAX([Mar-13]) AS [Mar-13],MAX([Apr-13]) AS [Apr-13],MAX([May-13]) AS [May-13],MAX([Jun-13]) AS [Jun-13],MAX([Jul-13]) AS [Jul-13]
 FROM @table
   UNPIVOT (
            tuax FOR tuay IN (totalUnitsAvail)
           ) tua
   PIVOT (
          MAX(tuax) FOR date IN ([Jan-13], [Feb-13], [Mar-13], [Apr-13], [May-13], [Jun-13], [Jul-13]) 
         ) p
 GROUP BY tuay
), rdm AS (
SELECT rdmy, 
MAX([Jan-13]) AS [Jan-13],MAX([Feb-13]) AS [Feb-13],MAX([Mar-13]) AS [Mar-13],MAX([Apr-13]) AS [Apr-13],MAX([May-13]) AS [May-13],MAX([Jun-13]) AS [Jun-13],MAX([Jul-13]) AS [Jul-13]
 FROM @table
   UNPIVOT (
            rdmx FOR rdmy IN (rentedDuringMonth)
           ) rdm
   PIVOT (
          MAX(rdmx) FOR date IN ([Jan-13], [Feb-13], [Mar-13], [Apr-13], [May-13], [Jun-13], [Jul-13]) 
         ) p
 GROUP BY rdmy
)
SELECT *
  FROM tua 
UNION ALL
SELECT *
  FROM rdm