I think that there are probably faster and better ways, but I think this is one way:

;WITH IndexColumns AS (

SELECT DISTINCT a.object_id, a.name, a.type_desc, b.column_id, TABLE_NAME=c.name, [COL NAME]=d.name

FROM sys.indexes a

INNER JOIN sys.index_columns b ON a.object_id = b.object_id AND a.index_id = b.index_id

INNER JOIN sys.tables c ON b.object_id = c.object_id

INNER JOIN sys.columns d ON c.object_id = d.object_id AND b.column_id = d.column_id

WHERE is_hypothetical = 0

),

CombineCols AS (

SELECT object_id, name, type_desc, table_name

,columns=STUFF((

SELECT ',' + [COL NAME]

FROM IndexColumns b

WHERE a.object_id = b.object_id AND

a.name = b.name AND

a.type_desc = b.type_desc AND

a.TABLE_NAME = b.TABLE_NAME

ORDER BY [COL NAME]

FOR XML PATH(''), TYPE).value('.', 'VARCHAR(MAX)'), 1, 1, '')

FROM IndexColumns a

GROUP BY object_id, name, type_desc, table_name)

SELECT b.type_desc, a.table_name, a.columns, b.name

FROM (

SELECT table_name, columns

FROM CombineCols

GROUP BY table_name, columns

HAVING COUNT(name) > 1) a

INNER JOIN CombineCols b

ON a.table_name = b.table_name AND

a.columns = b.columns

ORDER BY a.table_name, a.columns

It is not particularly fast but give it a chance and see what it gets you.

Edit: Improved the query speed, added remarks below and removed "hypothetical" indexes.

Remarks:

1) If a CLUSTERED index exists on the same fields as a non-CLUSTERED index, both are listed.

2) If two (or more) indexes exist involving the same fields but where the fields are ordered differently, these are also listed.