Looks like Apple is testing iTunes 4.9's podcasting support
The next version of iTunes, 4.9 is out grabbing podcasts from site around the web, likely from testers at Apple. Logs are showing a new user agents "Agent: iTunes/4.9 (Macintosh; N; PPC)" and then the podcasts are being downloaded.
Full story over at Make
Phill does not say if iTunes is downloading the RSS or just his files? That would be interesting to know.
Update: Talked to Phill, looks like iTunes has become an RSS Aggregator for audio enclosures. This brings in a whole lot of questions regarding quality of service if a user of iTunes subscribes to a feed that isn't so relaible or becomes swamped by people that see the podcast feed via the iTunes store.