Now I have Arduino Duemilanove that I have bought two weeks ago and it is marked 850 and have also *168 atmega Smiley what is the difference?? is it mistake??
The Arduino Duemilanove with ATmega328P started shipping from some distributors like Adafruit or NKC Electronics on February 28th. Other distributors after that. The price of both boards are the same, so if you purchased a Duemilanove board, and it didn't say anything about the new ATmega328P chip, then you received the correct board. If the distributor announced that they were shipping the new CHIP and you received the 168, then it was a mistake and you should contact your distributor.
Anyways, for $6 you can get a new ATmega328P MCU bootloaded for Arduino and have a spare, just in case.