http://www.japanesepod101.com/
This is perhaps the most popular and professionally recorded podcast for learning Japanese. There is free and premium audio and video content which included lesson notes and other learning materials.

Japancast.net
http://japancast.net/
Our competitors! A good homegrown podcast done by Paul and Hitomi Griswold. They regularly update their site and have plenty of content for you get your teeth into. Nice format and examples of Japanese from everyday life conversations and anime. Well worth listening to.

Osaka dialect 大阪弁 Japanese lesson in English
http://mayumik.seesaa.net/
I enjoy listening to this podcast as I used to live in Osaka and I can get my fix of the Kansai dialect. The format is simple but effective. You can read the entire transcript of the podcast in Japanese with an English translation. A very good learning resource for learning real Japanese in context.

S-J-P Study Japanese Podcast
http://sjp.cocolog-nifty.com/blog/
From what I’ve heard so far it is hosted by native Japanese with no silly gaijin to mess things up. Minimal English so it’s quite a good immersion into Japanese. Perhaps good for low intermediate and above. Unfortunately they haven’t updated their website recently.

The Linguist on Language
http://thelinguist.blogs.com/how_to_learn_english_and/japanese_podcast/
Not exactly a podcast but you can see Steve Kauffman’s youtube videos explaining how to learn languages all in Japanese. Check out his blog http://thelinguist.blogs.com/ which is concerned on general language learning. Steve’s bio is here: http://thelinguist.blogs.com/about.html Steve Kauffman is the brains behind Japanese LingQ.  Steve Kauffman is like El Gringo, a well traveled linguist but with suits.

Japanese LingQ
http://www.japaneselingq.com/
Podacsts are 100% ( from what I’ve heard so far) Japanese so good for total immersion if you are of an intermediate level. You have to sign up if you want to read the transcripts. It has some “revolutionary learning system” a rather questionable phrase in my humble estimation however it’s worth checking out.

Survival Phrases – Japanese
http://survivalphrases.com/japanese/guest.php
Very professional – annoyingly so. It’s so produced and corporate that it sounds like a commercial. Waaay too much English. But maybe good for complete beginners in Japanese.

Nippon Voice Blog
http://www.voiceblog.jp/nippon/
Hmm…Super zannen. I opened the page to find some long transcripts about Japanese culture. Great for reading and vocabulary BUT none of the mp3s were working. That’s probably something to do with the fact that the last entry was back in 2006.

If you know of any good podcasts for learning Japanese then feel free to post the urls in the comment section below. I’ll be sure to add it to the list here.