Good article.
Having that username/password in a batch file is an issue. If (for any reason, like the FTP server is down) the package fails, that file could be left behind, and then anyone could see it. You might be deleting it in the last step, but if the package fails before that step then that last step won't get run.
Wayne
Microsoft Certified Master: SQL Server 2008
Author - SQL Server T-SQL Recipes