Here are a few of those I listen to and find really nice. I haven't assessed them and its just my own opinion. Any further additions/comment/suggestions are always welcome.
- OWASP Security Podcast
rss feed: OWASP Security Podcasts RSS
hosted by: Jim Manico from Aspect Security
- MightySeek Podcast Postings
organization: NT Objectives, Inc.
hosted by: Dan Kuykendall
- Imperva Security Podcasts
Podcasts by Imperva range from Data Security to Cloud Computing to Saas but also include WAF, Web Application Sceurity, etc.
organization: Imperva Inc.
podcast link: Imperva Security Podcasts
- Cenzic Podcast Series on Application Security Mythbusters
rss feed: Cenzic Security Podcasts RSS
- Silver Bullet Security Podcasts
Security Podcasts by Cigital are not specifically targeted to Web Application Security but cover various aspects of Security
organization: Cigital, Inc.
rss feed: Silver Bullet Security Podcast RSS
hosted by: Gary McGraw