Commands We Can Use To Rename A Database In SQL Server 2008

http://www.mssqltips.com/sqlservertip/1891/best-practice-for-renaming-a-sql-server-database/
http://blog.sqlauthority.com/2007/07/13/sql-server-2005-use-alter-database-modify-name-instead-of-sp_renamedb-to-rename/

By SQL query

ALTER DATABASE MyOldDb MODIFY NAME = MyNewDb

Here
MyOldDb : It is already exist database which name will be change.
MyNewDb : It is new name of database which we will give to database


OR
By store proceudre
you cann use system store procedure which is sp_renamedb  Like

EXEC sp_renamedb 'MyOldDb', 'MyNewDb'

Here
MyOldDb : It is already exist database which name will be change.
MyNewDb : It is new name of database which we will give to database