Decide which Portuguese you want to learn: Brazilian or traditional. Podcasts exist for both. Refining your search will make finding the right podcast easier.
Type "Learn Portuguese podcast" into your favorite search engine. Read the descriptions of the search results. Open the ones that appeal to you simultaneously in multiple windows by right clicking the page and choosing "Open Link in a New Window." This will help you compare and contrast.
Read the description of each podcast. Get an idea of the method of instruction afforded by each. If you have iTunes, log on to the iTunes Store by clicking iTunes Store on the left hand menu. In the search bar, type the name of the podcast you're interested in. If the podcast is syndicated in iTunes, as most are, you'll be able to read reviews.
Download your podcast. On the podcast's hosting page, click the link labeled "Listen Now" or "Download." This will either stream or download the podcast. For flexibility, it's better to download. Alternately, download the podcast from iTunes by clicking the "Subscribe Free" button. Downloading will take between five minutes and an hour, depending on your Internet connection.
Upload the podcast to your MP3 player. Connect your MP3 player to your computer. Transfer the file by clicking and dragging the podcast from your desktop to the player. This step is unnecessary if you plan to listen to the podcast on your computer.
Listen to the podcast. If your MP3 player is an iPod or similarly menu-based, there is a "Podcasts" menu. Click on this to find your podcast. On your computer, right click your podcast and chose the "Open With..." option. From the menu, chose your preferred audio program. With either option, press "Play" to begin listening and learning Portuguese with podcasts.
Subscribe to your podcast. On the podcast's official website, click the "Subscribe" link. Or, on iTunes, click on the "Subscribe Free" button. ITunes will then ask you if you're sure you want to subscribe. Click "Subscribe" to confirm.