Hello Vinod Kumar,
There is an ATMEL 89 Series Flash Microcontroller
programmer (will program 89C2051 also) Ver 3.0 by
Mr. M Asim Khan, at this address
www.kmitl.ac.th/~kswichit/Pgm89v3_WEB/Pgm89v3.html
I built it a long time ago and it does work. It should
work on your 500 MHz PIII but if it doesn't you can get
a slower computer cheap. There are 75 million being
thrown away just in the USA alone. Good luck.
Regards,
Charles Bannister
programmer schmatic

adapater board

layout board