This script worked for me when I needed to script out the logins for each database, this script is using a stored procedure which you can find at the following URL: http://www.sqlserveroptimizer.com/2011/08/how-to-script-logins-from-user-database-in-sql-server-20052008-r2/

USE MyDatabaseName

DECLARE @login nvarchar(50)

DECLARE logins_cursor CURSOR FOR SELECT l.name FROM sys.database_principals u INNER JOIN sys.server_principals l ON u.sid=l.sid

OPEN logins_cursor FETCH NEXT FROM logins_cursor INTO @login

WHILE @@FETCH_STATUS = 0 BEGIN EXEC sp_help_revlogin @login FETCH NEXT FROM logins_cursor INTO @login END

CLOSE logins_cursor DEALLOCATE logins_cursor GO