You gotta love the way the Martins go from the doting, expectant grandparents who just want to preserve a piece of history for their progeny -- to turning over the tape of a private conversation to the democrats. Their story isn't even remotely believable. OTOH, you would think that Gingrich and the rest would have had the foresight to scramble/encrypt their communications.
A New Republic article I found online said that John Martin was a maintenance man at a public school near Gainesville, Florida while his wife Alice was a teacher's aide.
I've tried searching for their political activism and run into too many men named John Martin in Florida politics (even when I add the word democrats to my search).
Considering the level of their breach, they seemed to have disappeared from the public eye. There were several "remember back in 1997 articles" with McDermott's ongoing defense strategies but nothing to update us on the current activities of this couple that tried to take down the speaker of the house.
It has been theorized on other threads that this cell phone intercept story was just a coverup for a broader illegal wiretap of the Republican leadership. The theory is based on the contention that you can't technically 'hear' all sides of a conference call by tapping into a cell phone frequency that is part of the conference -- In other words, there must have been a illegal landline tap.