Is this what you're looking for?
SELECT
TableName = t.Name,
IndexName = I.Name,
FKName = fk.Name,
ReferencedTable = refT.Name
FROM
sys.tables t
LEFT OUTER JOIN
sys.indexes i ON i.object_id = t.object_id AND i.is_primary_key = 1
LEFT OUTER JOIN
sys.foreign_keys fk ON fk.parent_object_id = t.object_id
LEFT OUTER JOIN
sys.tables refT ON fk.referenced_object_id = refT.object_id
ORDER BY
t.Name, i.Name
Lists all the tables and the primary key index (if present) and any foreign keys (and what other table that FK references)