I have been working on an app very similar to Podcaster. It is called RssPlayer and it can be downloaded from the app store at http://itunes.apple.com/WebObjects/MZStore.woa/wa/viewSoftware?id=302006628&mt=8
It is basically Podcaster without the Search Directory. You must import and OPML or RSS feed. It has several features that Podcaster does not. Remebers your last play position in audio even when streaming. Follows human interface guidelines more closely. More Stable.
You can read more at http://rssplayer.blogspot.com