Far away is close at hand in the images of elsewhere.

Anon.

   DECLARE @D1 VARCHAR(20)
   DECLARE @D2 VARCHAR(20)
   DECLARE @D3 VARCHAR(20)
   SET @D1 = '01/12/2012'
   SET @D2 = '03/Dec/2012'
   SET @D3 = '01/01/13'
   SELECT CAST(@D1 AS DATE) AS 'was (dd/mm/yyyy)',CAST(@D2 AS DATE)    AS 'was (dd/mmm/yyyy)' ,CAST(@D3 AS DATE) AS 'was (dd/mm/yy'

Result:
was (dd/mm/yyyy)	was (dd/mmm/yyyy)	was (dd/mm/yy)
2012-01-12	         2012-12-03	           2013-01-01

   /* I used a temporary table BUT ONLY for illustration
        the values I used are from your posting Posted Today @ 6:13 AM  */

   CREATE TABLE #T (D VARCHAR(20))

   INSERT INTO #T(D)  
   VALUES ('01/12/2012'),('03/Dec/2012'),('01/01/13')

   SELECT D as 'Input value', CAST(D AS DATE) AS 'Output' FROM #T

Results
Input value                       Output
01/12/2012                  2012-01-12
03/Dec/2012                 2012-12-03
01/01/13	            2013-01-01

  CREATE TABLE #T (D VARCHAR(20))
   INSERT INTO #T(D)
   VALUES ('01/12/2012'),('03/Dec/2012'),('01/01/13')
   INSERT INTO #T(D)
   VALUES ('04/01/2013 15:02'),('21/Dec/12 2:17 PM')
   SELECT D as 'Input value', CAST(D AS DATETIME) AS 'Output' FROM #T

Results:
Input value	          Output
01/12/2012	         2012-01-12 00:00:00.000
03/Dec/2012              2012-12-03 00:00:00.000
01/01/13                 2013-01-01 00:00:00.000
04/01/2013 15:02         2013-04-01 15:02:00.000
21/Dec/12 2:17 PM        2012-12-21 14:17:00.000