There are some audio and video podcasts with the topic GIS available at iTunes. If you want to subscribe some Podcasts go to iTunes and search for GIS. Then you get some Podcasts from Universities or GIS companies. I listed some of these:
Einführung in die Geoinformatik (german):
From: Antonio Krüger, Uni Münster
Die Vorlesung „Einführung in die Geoinformatik” behandelt neben einigen zentralen Themen der klassischen Informatik, wie Datenstrukturen, Logik oder formale Sprachen, insbesondere Konzepte zum Umgang mit raumbezogenen Daten (Geodaten). Es werden verschiedene Ansätze der Modellierung von Geoobjekten aufgezeigt und in ihren anwendungsspezifischen Möglichkeiten und Grenzen diskutiert. Die Studierenden erhalten einen Überblick über die Methoden zur Analyse und Manipulation von Geodatensätzen, wie sie in den gängigen Geoinformationssystemen (GIS) Anwendung finden. Schließlich werden einige für die Geoinformatik typische Algorithmen erarbeitet, die zum Beipiel auf der Grundlage der Graphentheorie das Kürzeste-Wege-Problem lösen.

Spatial Thoughts GIS Podcast (english):
From: suchi
Spatial Thoughts GIS Podcast is the first and only podcast focusing on GIS and Remote Sensing happenings in and around India. It is our effort to bring you the most relevant and interesting stori es of the region in an enjoyable form. It is your chance to catch up with the industry buzz every week. So download an episode, sit back and enjoy!
GIS and Location Technology (english):
From: Farallon Geographics
No one does a better job of explaining GIS and location-based technology than the team from Farallon Geographics. Join us for our presentations and discussions on the latest trends and interesting applications in the GIS, Location Intelligence, and Spatial Information Management Industry.
ESRI Speaker Series Podcast (english):
From: Esri
The Speaker Series offers free short audio recordings that feature GIS technology insights from GIS users, business partners, and ESRI staff.
Autodesk University Geospatial Sessions (english):
From: Autodesk University
Geospatial session podcasts from Autodesk University. Learn tips, processes, and strategies that can enable your organization to harness the power of its data by bridging the gap between engineering and GIS departments, and the rest of the organization. Topics cover planning through design, construction, and maintenance using AutoCAD® Map 3D, Autodesk MapGuide® Enterprise, AutoCAD® Civil 3D®, Autodesk® Topobase™, Autodesk® Buzzsaw®, AutoCAD® Raster Design, and FDO Data Access Technology.
Written and submitted from Home, using my 802.11g WiFi network.