Just open query analyzer (or SSMS->query) and run the following against a database:
EXEC sp_MSforeachtable "exec sp_spaceused '?'"
This returns s list of tables, and the amount of usage they are using (rows + data usage)
name rows reserved data index_size unused
<name> 17991232 12636448 KB 11051664 KB 1583816 KB 968 KB
Enjoy!