The links to various free/opensource programs most useful and interesting of September:
CloseTheDoor identify open ports in your pc for better security
NewGen this app brings Metro UI to Windows 7, supports WPF, HTML5, and HTML widgets
Juice it allows to receive, listen and capture podcasts
NetbootCD install many Linux distro using one disc
Subsonic listen and share music in streaming, smartphone devices supported, it also allows to create a web music server