A/D conversion

[sunny]

hai all
i am almost new in this fourm and in electronics....
so pls help me..

my motive is convert analog voltage into digital and then back into analog...
first conversion, i mean A/D is done by the method underhere...
using pic16f877a

variable name =ADC_read(channel);



by this command ii have converted analog voltages into digital and stored in a variable... in the digital form...
now i want to get this digital data at the one pin of anmy port of the pic and then on any other circuit i want to convert back this digital data into analog....
is it possible by the way on which i am trying...?????

if not then i also have ADC0808 which is analog to digital and digital to analog converter....
but i don't how to use this for my purpose... help me in my problem...