Start with the Comic Book Podcast wiki and

ADD:
Great Xpectations
Pop Culture Leftovers
CMRO Podcast
Avengers Inspirations
DisOrderly Conduct
Comic Shenanigans
WNY Super Comics Podcast
Comic Cast
A Week in Geekdom
On the Rack
Comixbrew
Trentus Magnus Punches Reality
Caffeinated Comics
Real Books Don't Have Batman
Superheroes Speak
I Hate Comics
Alternative Press
Stack of Comics
Batchat
Let's Talk Comics
Saturday Morning Comics


These shows have faded:
About Heroes
Alternate Cover Comics: Warrior Code
The Bat Radia
BOING the podcast
Comic Book Fury
Comic Critique podcast
Comic Kings
ComicCast
Darkhan City Awesome Comics Culture Podcast
The Fanboy Scoop
Fanboy Tollbooth
Geek World Order: Covert Cast
The Thrilling Adventures of Superman
Lanterncast Presents Elseworlds
Lantercast Presents Green Lantern-Green Arrow
Probably Comics NOW! podcast
Raynman Power Hour
Rochetbot Radio
Shed Talk
Shed Talk: Step into the Shed
Supergirl's Might
Supergirl's Finest
Tales from the Parent's Basement
Tell Me Something I Didn't Know
WCBJ Radio
We Talk Comics: MoJoe the Mo and Joe Show