What’s an aggregator/podcatcher?
An aggregator, AKA podcatcher, is a piece of software that allows you to “subscribe” to an RSS or XML feed and it then automatically downloads the files/lectures you have subscribed to and automatically inserts them into your desktop music player, whether it is iPodder or Apple iTunes. Once the audio file has been added to your music library, the next time you dock and sync your portable MP3 player the files can be automatically moved over and ready for you to listen to.