How To Set Autogrowth Off / On (T-SQL)

I am testing a msde 2000 sp4 database. (would like to use it against sqlserver 2005 later)
I need to turn the property for autogrowth on and check that an application alterts the user that it is on

and then off and verify the user is altered that it was set off.

I am not sure if this will work for mydb and mydblog
--turn off autogrowth
USE master
GO
ALTER DATABASE mydb
MODIFY FILE
(NAME = mydb,
FILEGROWTH = 0MB)
GO

--turn on autogrowth
USE master
GO
ALTER DATABASE mydb
MODIFY FILE
(NAME = mydb,
FILEGROWTH = 10MB)
GO

USE master
GO
ALTER DATABASE mydblog
MODIFY FILE
(NAME = mydblog,
FILEGROWTH = 0MB)
GO

--turn on autogrowth
USE master
GO
ALTER DATABASE mydblog
MODIFY FILE
(NAME = mydblog,
FILEGROWTH = 10MB)
GO


Also I need to know the t-sql for setting unrestricted growth on and off but I can not seem to find that.

Any help would be great.

We can not use enterprise manager so I'm planning to use osql thru a cmd prompt.

thanks
ced