I noticed not too long ago that iPodderx had gone away, so I have since removed it from the list of podcast aggregation services. It was sued by Apple and forced to change the name of their application. If it comes back, I will add it again because it was supposed to be a really good application.
I tested out another podcast aggregator called Juice, which hogged some serious resources on my laptop. It also was not very user friendly, didn't make it easy to find podcasts, etc... I have removed it from my system.
If anyone knows of or uses a podcast aggregation client or service and likes it, drop me a line at paul /at/ pauldotcom.com