Apple's iPhone already features a number of calling options once you are connected - including adding a third line, hitting mute, putting the call on speaker, and putting calls on hold. Given the iPhone's parallel option to record audio, why not add a red "Record" button alongside the conversation?
Before privacy and security advocates call foul, I assume it is very simple to have a mandatory introductory audio phrase, like "this call is being recorded", as well as beeps along the way.
Marrying Voice Memos With Phone Calls Should Be Easy
Today's world of podcasting usually deals with a third party hosting service, like Talkshoe, or gathering all parties on a Skype call, while one person manages the process. I think it would be dramatically easier to use the same way you make any other call, and just have Apple do the work of gathering the call into an MP3 file, and making it available in your iTunes for later listening, so you can upload as you please.
In theory, if Apple could enable this "Record" calls functionality, we would only be a few steps away from what could be seen as a panacea, not just for podcasters, but anybody conducting interviews. It shouldn't be too hard for a phone call to take place and to identify words and phrases by phone number (or the Address Book contact) of the person speaking. At that point, you could run the information against a new application, and have the call automatically transcribed. While this may sound like fantasy, the world we live in isn't that far from delivering excellent speech to text functionality. Pointing that tech at a recorded phone call you make on your iPhone shouldn't be that much more difficult.
Let's just turn on the record button and go.