Some of the highlights from my perspective:
1. 10% of all Feedburner feeds are podcasts; there are 6,000 podcast feeds out of 60,000 total RSS feeds.
2. The rate of growth is increasing, which is a leading indicator. What was a rate of 800 new podcast feeds per month is now almost double.
3. Podcatchers such as Doppler and iPodder are now in the top 25 feed readers. Watch for some of these multifunctional apps to double as a standard text-based reader. On the hand, look for more of the standard RSS readers to support enclosure tags and audio\video content downloads.
Based on the number of podcasts tracked at some of the major directories, it's apparent to me that Feedburner has a lion's share of the podcasting RSS feed creation. As a result, the entire story and these statistics within it are a nice "crystal ball" of the podcasting market.