Space Used by Database and Table in Sql Server

How to know how much space is consumed by your database.
Exec sp_spaceused
Output
database_name database_size unallocated space
------------------------------------------------ ---
Northwind 58.38 MB 8.23 MB
reserved data index_size unused
------------------ ------------------ --------------
12056 KB 10464 KB 1104 KB 488 KB
How to know how much space is consumed by each table in your database
EXEC sp_MSforeachtable @command1="EXEC sp_spaceused '?'"