The shoe phone has morphed into a tie fax, but would you believe? Get Smart is returning with new episodes. As of Jan. 8, Fox brings the '60s spy spoof into ; the '90s, with Don Adams as the wall-bumping Maxwell Smart and Barbara Feldon as his velour-voiced wife, Agent 99. Here, on the eve of their comeback, they compare notes on... The laugh track Feldon: ''You need a laugh track. Laughter inspires laughter.'' Adams: ''It drives me crazy. Whoever they put on the laugh track (in the original show) was pressing that button every four seconds even on the straight lines.'' Handiwork Feldon: ''I used to make pillows out of 99's miniskirts.'' Adams: ''I once tried to put a crib together, and after seven hours I threw it out the window.'' The fans Feldon: (who's a New York resident): ''The other night I came out of an ice cream shop and about eight kids were lined up with their shoes to their ears.'' Adams: (who's a Californian): ''When you live in L.A., nobody bothers you.'' Interim gigs Feldon: (who's a veteran of commercial voice-overs): ''I get to do lots of cold remedies I think because my voice is considered soothing.'' Adams: (who lent his nasal tones to Inspector Gadget cartoons): ''I never saw one of them. They aired at 8 a.m. on Saturdays. I wouldn't get up for the Second Coming at 8 a.m.'' Reuniting Feldon: ''It's like Pavlov's dogs. I hear (Don's) voice and 99 automatically comes out. Or at least salivates.'' Adams: ''Barbara is the great joy of coming back and working. She's one of the great ladies of all time.'' Reruns Feldon: ''I've seen about three episodes since 1970. I thought they were absolutely delightful though I did regret some of the clothes.'' Adams: ''If I'm bouncing around the channels and there's no one on Letterman or Leno, I'll watch (the reruns on Nick at Nite). Some of the stuff was so funny, you can't help but laugh.''