No. You can just as easily listen via your computer.
All you have to do is go to download iTunes (for free), go to their iTunes store, then click on Podcasts.
You will then have access to literally THOUSANDS of podcasts, all for free. You can either download single episodes, or subscribe, which will mean that iTunes will search for the latest episodes and put them in your "Podcasts" folder.
Simply look around the catalogue to find what you want. Or to search for specific podcasts, use the "power search" link on any iTunes store page.
In addition to the NTCoF, some of my favorite atheist podcasts are: American Freethought
Point of Inquiry
Dogma Free America
The Skeptic's Guide to the Universe
And some I listen to just for laughs & : The Bugle
Real Time with Bill Mahr
NPR Sunday Puzzle
Old Time Radio Comedy
Wait, Wait, Don't Tell Me