sairam, Thanks madam for directing me to saikingdom.com.
i'm halfway through the book. Till now, i have only heard the lunar year calculation that works out to around 95 years, regarding Bhagavan's age at the time of His departure from physical plane. This is also the explanation i offered to many newbies. The book "Sai Thy Kingdom Come" tells some new things.
The exact timing of Bhagavan's re-appearance is unknown going by what is mentioned in this book. It certainly raises hopes in the hearts of devotees, the possibility of being blessed by Bhagavan's darshan once again.
Let us hope to see what surprises Bhagavan has in store :-)