First best answer.. :>

Got a best answer at yahoo answers.. [link]

(open secret - mine is the only answer to the question.. but 'm taking it as no body even dared to answer that question.. ;D )

and atleast now i got
- 10 bonus point (adds more value to my YA a/c) ;>
- a mild morale boost..

Link:
Is P89C51 I2C compatible?
http://answers.yahoo.com/question/?qid=20080508004034AA6zXVw