gPodder is a podcast manager written in Python with a GTK interface. After telling it which podcasts you like, it sits in the system tray, regularly checking for updates to your favourites. When an update becomes available, gPodder downloads it ready for you to listen to. Once downloaded, you can listen to it through gPodder or transfer it to another device like an MP3 player, mobile phone or iPhone.
Many of the options can be changed, automatic downloads can be turned off if you want control over when podcasts are downloaded (some ISPs restrict daytime bandwidth), and the players used for audio and video podcasts can be changed. Podcasts are usually announced by RSS or Atom feeds and gPodder subscribes to these, and Soundcloud feeds, to know when new episodes are available. There is also a searchable list of top podcasts, so you can browse for new ones to subscribe to. The my.gpodder.org service lets you upload and download subscription lists, handy if you want all your podcasts available at home and at work.