DIYbanter - need a level-holding circuit

After 2 days of trying combinations of search terms in Google, I've given
up. I'm searching for a chip or circuit that can accept as input either TTL
level address lines, or a serial input (either will be from a basic stamp,
if that helps any), and sets a corresponding voltage level between 0 and my
circuit's max voltage, and then (the important part) holds that level with
no further input. I'd like to be able to route the input to whatever I want
to set the voltage level on, send it a signal as per above to set its
level, then set route it elsewhere to set something else's level, etc...

The name of a circuit, IC, or component designed to convert-and-hold the
input signal from one thing into the output voltage of another thing would
be plenty.

Thanks a lot for any help on this one.
--
Gary Fixler
Savage Entertainment, LLC