See my response(s) to you in your other thread(s). It would probably make sense for you to keep your questions about this subject within one thread, really, since it feels like you are basically asking the same question over and over again. 😉
I will say, in response to your comment about a combination mic+speaker attachment, that if I recall correctly (and it has been a while since I have really been involved in this scene), there have been some people who have tried the combo mic+speaker-through-the-dock-connector attachments, and had more trouble getting them to work with the iPod Touch than the microphone-only models. (One example of such a device is the MacAlly iVoice Pro, I think it's called.) I want to say that either the speaker would work but the Touch would flat-out not detect the microphone, OR that they would both work but there was no way to turn the speaker output off, so you'd get a nasty feedback loop going if you tried to use it with a microphone-aware app.
-- Nathan
