clipped from: www.apple.com 
When you find a podcast you love, you may want to share it with others. You can grab links to a podcast in the iTunes Music Store by hovering over the “cover art,” right clicking, and selecting “Get iTunes Music Store URL.” With the URL in your clipboard, you can paste it into an email, a chat, or a web site. Use the same process to get links for subject rooms, podcast episodes, artists and today’s top podcasts.
Or, if you already subscribe to a podcast you want to share, simply drag it from your podcast’s source to your desktop. That creates a standalone .pcast file that you can email to friends as an attachment. If they have iTunes, clicking on the .pcast file will automatically subscribe them to the podcast, and iTunes will immediately begin to download the most recent episode.