Once you are subscribed, iTunes will now fetch the RSS feed's XML file regularly to see if there are new podcast episodes. Whenever there are new episodes, iTunes will download these automatically, and will synchronize the audio files to your iPod the next time you plug in.
Podcast settings - You can configure how often iTunes will check your subscribed podcasts for new episodes. Under the Podcasts tab in iTunes preferences, you can change the frequency for checking new episodes, and you can define what the application does when there are new updates. You can set this to automatic, or you can set it to manual. When the setting says "Download Most Recent Episode," shows are downloaded automatically. When it says "Do Nothing" then you have to manually click the "Get" link to download each episode. Lastly, you can choose how many episodes to keep. You can keep all Cigarettes Online Free Shipping, or you can set a limit to the last few episodes, to save on space.