"well i am new to microcontroller world"
Welcome!
"I need help regarding my project . its like to input data through keyboard"
Do you mean PC's keyboard?
"and using serial port connected to microcontroller"
What do you need the serial port for? if you are using PC's keyboard then you need port pins as clock and data ( Read about interfacing PC's keyboard there are links in here if you do search)
"it displays it on LCD."
Read about LCDs in the tutorial section.
"I need help in what microcontroller(....8951?) should i use"
It depends on the availabilty of microcontroller in your reagon and on the availability of programmer. If you don't have a programmer use one that supports flash magic, which is programming through a normal serial port of the PC(no hardware required) or use cygnal development board with 99$ you get a development board with JTAG interface.
" and , what type of LCD would be suitable ."
Any type that has multi line and LCD controller built in, most of them rely on the HD44780 controller built in, read the datasheet so that you understand how to interface it.
" and i know C programming , so would it be possible using C programming . bcoz here i have seen some assembly code"
Yes it is possible to use all C for your application but since you are new to the microcontroller world it is better for you to start with assembly so that you understand the hardware better, once you master it then you can switch to C language to get the best out of both worlds.
"i would be greatful for your help in this regard. if u can guide me step by step what to do .
thank you . "
Start your journey into the microcontroller world and if you have any problems just post your questions here and we will all help you.
Hint: start one step at a time and break your project into smaller modules that you can test alone and connect them together to make the full working project.

Regards
Mahmood