How to capture the url of a podcast out of iTunes, appropriate for emailing or imbedding in a blog.
In the left sidebar click on Podcasts
Click on Podcast Directory in the bottom right corner of the iTunes window.
Click on the image for the podcast
You'll be given the option to copy the url of the podcast in the iTunes store.
Paste into your favorite application.
When your recipient clicks on the link, it will launch iTunes, and take them right into the podcast directory ready to click the Subscribe button.
Just by way of example, here's the url to subscribe to the NosillaCast