dropped iphone 4s

Usually, after troubleshooting the phone with Apple employee, they would recommend a replacement for this. They would investigate the cause and if it will proven that this is a Customer Induced Damage, I'm sorry but there would be no free replacement here.

That's what I believe.

thanks i went to the apple service center..but the solution team of apple service center told me that they dont do some repair stuff or even free replacement...they will replace my iphone with brand new with charged..like buying a new iphone 4s but i went to another service center..they dont do replacements..but they will send my iphone to the main apple service center..which is located in singapore...but when i asked how much will it cost me from sending my phone to singapore..they told me they dont know.... wew!! but thanks for your reply...

.but the solution team of apple service center told me that they dont do some repair stuff

That is correct. Apple and authorized Apple service centers do not repair iPhones, they replace them

or even free replacement...

That is also correct. User-caused damage voids the warranty, even if a problem existed prior to the damage. You will have to pay for the iPhone to be replaced.  You will need to ask an authorized service center about cost. You can locate such a service center via this page:

http://www.apple.com/sg/service/

Regards.

THANKS A LOT