CREATE TABLE #Dob(birth VARCHAR(15))
   INSERT INTO #Dob
   SELECT '24-10-2012' UNION ALL
   SELECT '01-01-2011'
   SELECT birth AS 'Input',
   REPLACE(birth,'-','/')AS 'Converted' FROM #Dob

Results:
Input	        Converted
24-10-2012	24/10/2012
01-01-2011	01/01/2011

DECLARE @Dob TABLE (birth VARCHAR(15))

INSERT INTO @Dob
   SELECT '24-Oct-2012' 
UNION ALL
   SELECT '01-Jan-2011'
   
SELECT birth AS 'Input'
, CONVERT(VARCHAR(15), CAST(birth AS DATETIME), 103) AS 'Converted' 
FROM @Dob

Input           Converted
24-Oct-2012	24/10/2012
01-Jan-2011	01/01/2011