dear friend,
Actually there is no three months notice period as every one claims, yet, three months is being followed for making alternative arrangements, In the Govt Sector, there is one month notice period of pay one month salary for immediate relief that is really the right direction to follow, since, keeping an employee who is not interested is not a worthy decision. I do enclose a copy in this regard. If the post is confirmed then three months notice is advisable duly considering training provided to the employee etc.,