Do you need instant notification?
You could achieve this with a trigger on the table calling database mail. I'd be wary of making changes directly to 'system' tables like this though.
Another way would be to create a job that returns the results for the last day/hour - whatever frequency works best.
This would show any items created the previous day: (note this includes folders, datasources etc, not just reports)
SELECT u.UserName, c.CreationDate, c.Name, c.[Path]
FROM dbo.[Catalog] c
left join dbo.Users u on u.UserID = c.CreatedByID
where c.CreationDate >= CAST(CAST(DATEADD(DD, -1, GETDATE()) AS DATE) AS DATETIME)