A long time ago you could modify a RadioShack dialer so it would play tones that simulate money was dropped into a payphone. Well, now it’s time for the old to meet the new. Here’s a How-to for doing this with an iPod- the ability to do this has been turned off on payphone for years now but it’s a fun thing reminisce about. I think the iTalk would be the best way to do this for playback if it were to work. Link.
How-to: Phreaking your iPod