To date, Vemail has allowed Verizon customers to have email send to their phone to be "read" to them and reciprocate by speaking emails that would be sent as an audio link to the recipient.
The technology has been expanded to allow what some are calling mobilecasting.
I'm not sold that this actually fits the bill as "podcasting". My single criteria for determining what is a podcast and what is just a file on the web is the presence of an RSS feed that can used in conjunction with a podcatcher to fulfill the "cast" part of the deal. I'd need more information on the nuts and bolts of the process to make a determination.
From a value perspective, something like Gabcast seems to be a better solution. There are a variety of ways in which to call in and record a mobile cast (which means anyone can use it) and Gabcast offers an RSS feed.