I use sigmatel S90 it is very nice phone but recently wheneve i call to anyone or somebody call to me i am able to listen their voice clearly and but they can't able to listen my voice on other end and they told that i listen my voice in improper in very high pitch,,,,,,,,,,olz solve it it is very urgen

This problem has been found in many of the sigmatel s 90 handsets sold out
I had the same problem
there is a problem with the mic and has to replaced
IF you do not want to incur any additional costs
then i will advice you to use the headset provided and use the mic include in the headset
you will notice that the Listner receives your voice clearly....
If you have any more questions you could ask me