There's an anonymous (damn!) list of companies who have failed in their podcasting efforts for a variety of reasons in Leesa's post. I wish I knew who they were because I'm a nosy guy, but I guess I'll have to live without it.
I can see where Leesa is coming from. I've no interest in being a consultant, but I am constantly striving to get a book deal. I have an agent who helps me tailor my proposals and sends it to all the right people. He takes a percentage off the top of any book deal that I may get, but I'm pretty convinced that he'll get me at least that much more. In effect, he's going to pay for himself.
It's much the same idea with corporate podcasting. Hiring someone who knows what's going on in a given field is almost always going to save money in the long (and short) run. The podcast, in this case, is likely to be better received, of higher quality, and generally enhance the brand rather than destroy it.