Mic not working on iPhone?

For info on backing up not to mention restoring your iPhone
http://support.apple.com/kb/HT1414
Seems a bit weird that the mic works in speakerphone but not normally but for that part i have to bow out i haven't been in or seen discussions in regard to it but hopefully the above link at least gives you the backup information you where after. Otherwise the only advice i would give would be to try the usual re-boot/reset/restore advice that solves a lot of issues after the 3R's the genius is the next step

I seem to have exactly the same problem with my iphone. The mic on my iphone doesn't seem to work except when I'm either on speakerphone or have my headset plugged in. I basically can't be heard at the other end. Have you been able to fix iPhone? If so, please let me know how.

FM

Hi, I hvae the sma eproblem with my IPhone 3G. This only occured3 days ago.
The Mic just stopped working, but the speaker phone works fine during calls. i.e. when making/receiving calls the other side cannot hear me.
I tried trouble shooting every possible step advised by Apple i.e. trying this with my other mobile; replacing the SIM, restoring as well as erasing all content and restoring to factory settings- ut nothing has worked.
My phone is hardly 7 months old and have bought it at an exorbitant price trusting the Apple brand!!!,
Now i've given my phone back to the cell company-Aitrel that i bought the phone from and the treatment and professionalism is absloutely astounding.
the clerk gave me a 'hand written' receipt fot the most expensive phone on their counter as a service receipt saying the phne should be ready in 20 days after a service and check
I need and want a bloody replacement or my money back...I think Apple/iphone is a big rip off....I could a bought a chinese immitation for quarter the price and got the same service!!!!

I'm having the same issue, and I'm not having any luck finding a solution. I've even restored it to factory settings. I really would like someone to give a fix for this issue!