I started a podcast back in April and went with a 50GB a month plan and quickly exceeded my bandwidth. The next month I passed the hat to all parties involved in the podcast and collected enough money to get an older box (P3/40GB disk) running over a 10Mbit connection w/ 4TB metered bandwidth (more than I could possibly use). I'm lucky to have a buddy that runs a small hosting company piggybacked in the same facility as 2 very large ISPs in Atlanta.

When you're doing a podcast you need to really consider what kind of content you're pushing. This will determine the bitrate and file size. Our podcast consists of DJ sets running 80min encoded at 192kbps (or VBR with the final file around 100MB). On average we push 1600 downloads a week on new episodes and 4000 complete downloads a week on archives. You'll also have about 20-to-40% more traffic going to partial/incomplete downloads. We recently starting doing podcasts at work based on my experience with my out of work project. The requirements are very different since we're doing 15min shows with all voice content, the files are encodded at 32kbps. With the smaller files, you're hosting requirements are not much different than regular web hosting.

I've been tweaking our apache configs for months trying to tune optimal levels, but I'm still not 100% convinced we're there yet. If anyone has config tips for apache to optimize large file transfers, please.. I'm all ears.

I recommend that go for some paid hosting server where you can easily upgrade. Run some blogads or something to help recover the costs. We've always just broke even.

Also, I highly recommend that you use Feedburner for your RSS feeds. You get all kinds of great stats and subscription options in a browser friendy format if someone views your raw feed.

Here's an example:
http://feeds.feedburner.com/ABrooklynLifeRadio

Also, here's the podcast blog:
http://www.abrooklynlife.com/podcast/

Cheers,
ABL:Radio

if anyone is interested in the buddy of mine's ISP, you can reach me though the email link on our blog.