linking 2 NXTs for shared tasks

Hi folks,
I;ve been playing with the NXT, nad I've got a couple fo situations where
I'd like to have additional inputs. I was wondering if anyone has found any
decent way to link 2 of them so that one control sthe other (code runs on
one until to either control or call subs on the second).... I can think of a
bunch of mechanical linkages to get the job done, but code is so much
easier...
thansk
_JD