i can hear when some one call me but he cant hear my voice

Try restarting your iPhone by holding down the on/off and home buttons at the same time until you see the Apple logo.

See this about resetting the phone http://support.apple.com/kb/HT1430

PLEASE turn off your Caps Lock. That is considered yelling on the Internet. No need to yell. If a reset did not fix the problem, a restore is the next step. http://support.apple.com/kb/HT1414 will explain a restore.

Try this with the screen unlocked, press up or down on the volume controls on the side. Does it say headphones? If yes, then try cleaning the headphone port with compressed air.

Compressed air or you can put your head phones jack in and out rapidly about 5 or ten times.