IPhone 3G internal microphone?

[Luciusfilmex]

Does anyone know the characteristics of the internal microphone in the IPhone 3G?

I've been surprised by the quality of the mic, even replacing my headset's microphone.
Does anyone know the specs/characteristics? Typical mic info, like if it's dynamic/condenser, etc.

I'm currently looking for a real microphone, so I need to know what I'm putting it against.

Thanks for your time!
Luciusfilmex