
In no particular order, I have here a list of some of the best and highly recommended Linux/FOSS podcasts of 2008:
Linux Outlaws

This interesting description of Linux Outlaws as seen on their website accurately describes the show:
Linux Outlaws is a podcast about Linux and free and open source software. We are normal users like yourself rather than part of the in-crowd of community leaders and hardcore kernel hackers. On the show, we talk about interesting news and developments and stuff that we come across in our daily usage of Linux, often with a serious attitude and a humorous angle (the podcast has been described as being "very laid-back" by listeners and reviewers alike). We don't claim to be gurus or experts on anything, but we're trying very hard to provide you with a good time and interesting information.
The chemistry between Fabian (the German guy with a funny accent and a tongue-in-cheek humor) and Dan (the laid-back British open source enthusiast/musician/programmer) is so great making Linux Outlaws a podcast worth listening to.
FLOSS Weekly

FLOSS Weekly is purely an interview type of podcasting with famous guests from the free and open source software community. Their long list of prominent guests include Guido van Rossum, Jimmy Wales, Jon "maddog" Hall, Rob Malda, Jeremy Allison, and many others.
With great hosts and equally great guests, FLOSS Weekly can’t go wrong. The show has always been interesting, and listening to it has already become a weekly habit of mine.
The Linux Action Show

The Linux Action Show starts with Bryan’s animated intro summarizing the hottest stories of the week. The show features discussion about FOSS, a call-in question-and-answer segment, and news about events and issues in the Linux community.
The Linux Action Show has already interviewed a good number of famous FOSS developers, advocates, and entrepreneurs including Mark Shuttleworth, Jono Bacon, Justin Steinman, and Kevin Carmony.
The Linux Link Tech Show

Broadcasting live on the internet every Wednesday with a podcast version available shortly after, TLLTS has already produced more than 250 episodes. TLLTS has been visited by some of the most notable free and open source personalities like Richard Stallman, Chris DiBona, Bruce Perens, Ian Murdock, Patrick Volkerding, Mark Shuttleworth, and many others.
TLLTS is loaded with fun-filled discussions on the latest news in FOSS, and the show is also known for running gags and goofs. You can also learn a lot of useful information from listening to TLLTS since some of its hosts are considered gurus/experts in their own field.
LugRadio

LugRadio has been featured in Linux/FOSS-related magazines such as Linux Format, Linux User and Developer magazine, and Linux Magazine. The show was also mentioned by many popular websites including Slashdot.
In July 19 2008, at the annual LugRadio Live UK event, the LugRadio team bade farewell to their listeners. However, it was announced that there would still be a LugRadio Live 2009 even though new episodes are not being produced. Though the show has ended, their loyal fans will always remember their rock and roll style of podcasting. You can still download and listen to all the LugRadio episodes HERE.