Creating a user and giving permissions in database

Sometimes we need to create special users for our database. For example, in one of my applications, I need to provide appropriate permissions for remote server window service (which is running as a local system account on remote server), so that it can connect to my database and can perform read-write operations. I found following links helpful for understanding basics of SQL server security:

http://vyaskn.tripod.com/sql_server_security_best_practices.htm

http://msdn.microsoft.com/en-us/library/ms187750.aspx

To cut long story short, following is SQL command to create and give read-write permissions to remote machine. Suppose remore server name is 'TESTDOMAIN\testserver'.

Go
IF NOT EXISTS (SELECT * FROM master.dbo.syslogins WHERE loginname = N'testdomain\testserver$')
 CREATE LOGIN [testdomain\testserver$] FROM WINDOWS
GO

IF NOT EXISTS (SELECT * FROM dbo.sysusers WHERE name = N'testdomain\testserver$')
 CREATE USER [testdomain\testserver$] FOR LOGIN [testdomain\testserver$] WITH DEFAULT_SCHEMA=[dbo]
GO
GRANT CONNECT TO [testdomain\testserver$]
EXEC sp_addrolemember 'db_datareader', 'testdomain\testserver$'
EXEC sp_addrolemember 'db_datawriter', 'testdomain\testserver$' 
GO

GO