How to find missing indexes in SQL Server 2005 and 2008

SELECT
[Impact] = (avg_total_user_cost * avg_user_impact) * (user_seeks + user_scans),
[Table] = [statement],
[CreateIndexStatement] = ‘CREATE NONCLUSTERED INDEX ix_’
+ sys.objects.name COLLATE DATABASE_DEFAULT
+ ‘_’
+ REPLACE(REPLACE(REPLACE(ISNULL(mid.equality_columns,”)+ISNULL(mid.inequality_columns,”), ‘[', ''), ']‘,”), ‘, ‘,’_')
+ ‘ ON ‘
+ [statement]
+ ‘ ( ‘ + IsNull(mid.equality_columns, ”)
+ CASE WHEN mid.inequality_columns IS NULL THEN ” ELSE
CASE WHEN mid.equality_columns IS NULL THEN ” ELSE ‘,’ END
+ mid.inequality_columns END + ‘ ) ‘
+ CASE WHEN mid.included_columns IS NULL THEN ” ELSE ‘INCLUDE (’ + mid.included_columns + ‘)’ END
+ ‘;’,
mid.equality_columns,
mid.inequality_columns,
mid.included_columns
FROM sys.dm_db_missing_index_group_stats AS migs
INNER JOIN sys.dm_db_missing_index_groups AS mig ON migs.group_handle = mig.index_group_handle
INNER JOIN sys.dm_db_missing_index_details AS mid ON mig.index_handle = mid.index_handle
INNER JOIN sys.objects WITH (nolock) ON mid.OBJECT_ID = sys.objects.OBJECT_ID
WHERE (migs.group_handle IN
(SELECT TOP (500) group_handle
FROM sys.dm_db_missing_index_group_stats WITH (nolock)
ORDER BY (avg_total_user_cost * avg_user_impact) * (user_seeks + user_scans) DESC))
AND OBJECTPROPERTY(sys.objects.OBJECT_ID, ‘isusertable’) = 1
ORDER BY [Impact] DESC , [CreateIndexStatement] DESC