You're looking for Rockport Oxford-style shoes. Rockport's the brand.
EDIT: The shoes in the first MIB were specifically the Rockport Pallas. I don't believe they make them anymore, but there are similar ones listed on the web store. I'm not sure what they wore in MIB 2 and 3.
I own a pair. I didn't buy them because they were used in the film, but let's face it, I'm a geek. It was a factor.
EDIT2: I'm not sure I'd recommend them if you don't wear suits and such very often. They're not cheap, and are slightly more than I would typically spend on footwear. But they are comfortable and very tough - presumably why they were picked as something to actually film a movie in. I've had my pair for around ten years now.
-- Acyl
EDIT: The shoes in the first MIB were specifically the Rockport Pallas. I don't believe they make them anymore, but there are similar ones listed on the web store. I'm not sure what they wore in MIB 2 and 3.
I own a pair. I didn't buy them because they were used in the film, but let's face it, I'm a geek. It was a factor.
EDIT2: I'm not sure I'd recommend them if you don't wear suits and such very often. They're not cheap, and are slightly more than I would typically spend on footwear. But they are comfortable and very tough - presumably why they were picked as something to actually film a movie in. I've had my pair for around ten years now.
-- Acyl