There are many podcast feed aggregators available. Here are the ones that I obtained by doing

apt-cache search podcast

on my debian machine.

• democracyplayer - GTK+ based RSS video aggregator
• hpodder - Tool to scan and download podcasts (podcatcher)
• kitty - a Qt/KDE based RSS podcast and video aggregator
• podracer - podcast aggregator/downloader
• rhythmbox - music player and organizer for GNOME