Dear Irfan,
I do not know, how much you know about the subject already...
Do you know how a cpu work, what is clock, what is hi lo etc.
If you do not know how to get a 89c2051 work in smallest circuit, then I would recommend you to learn such thing by yourself, through some classes or by the help of some good book. There are plenty available in Pakistan and in India.
Otherwise you might not get anything but confusion.
But if you know the things i mentioned above, then visit Atmel site www.atmel.com, where you will find enough informations in application notes.
goodluck

Rauf