You can find it through two ways

a) Query Analyzer.
b) SSMS/Enterprise Manager.

a). Query Analyzer :

1. Sp_helpdb — execute this is master database.
Output : you will get information about all databases sizes.
2. sp_help ”database_name” —
Output: gives in detail information about Log and data file, with their sizes.
2. Sp_helpfile ( execute in the database for which you want size). Will give the same information about log and data file of the current database.

b) Enterprize manager: Expand Sql Server – Expand databases- click on database name = right click on database name – view – all task and then you can see in detail information about the size of the log file and also data file. And also you can see how much is filled, how much is empty.
b) in Enterprise Manager – right click database name , click properties, you will see the database size.
c) SSMS (2005) : Right click database select reports- click standard reports – Disk usage. you will see a report and you can see all details about sizes. If you expand the last point ” Disk usage by datafiles” you can see some good information.
d) SSMS (2005) – Right click database name, click properties and you can see database size.

To see the only logspace for all databases. Execute this statement,

DBCC SQLPERF( logspace)

Output: Will give you detail information about Logfile of the database.

your second question about tables:

Please visit this link : http://blog.sqlauthority.com/2008/07/08/sql-server-find-space-used-for-any-particular-table/

Hope this helps.
Thanks
Imran.

1.What is the current file system size of the database?

2. What is the current size of the tables (used)?