answering machine kinda facility for cellphones??

i was thinking if this facility is available for cellphones. like i had an answering machine landline phone before and i could record my own voice message and whenever i go out i would enable that function. if anybody called then, after 2 rings, the answering machine would come on and request the person on line to record a message.. can this be done with cell phones??

if it is not free.. what are the rates for airtel?