I have just watched the first 4 episodes of the colorized DVD version and I am very impressed. I read earlier that the show was originally filmed in black and white so my question is how do they colorize it? Hopw did they know what color everything was supposed to be (for example..the clothes, cars, etc) anyone know?

I think they just guess.

they colorize it with a computer

Each episode is lined up, frame by frame, and a computer colorizes it. It's a painstaking process, that must be done neatly and delicately.

I have just watched the first 4 episodes of the colorized DVD version and I am very impressed. I read earlier that the show was originally filmed in black and white so my question is how do they colorize it? Hopw did they know what color everything was supposed to be (for example..the clothes, cars, etc) anyone know?
Yeah, they only colorized the b&w eps. recently using modern technology. Before that, those early eps. were just b&w back when it was on Nick at Nite in the 1990's.

It is colorized with the help of a computer. I love colorized movies and TV shows, prefer to see them in color instead of b/w anytime. But how it works is a human being called a colorist assigns a particular color to each and every item in the frame of a picture. The computer then puts that color into that item in every frame of the program. Today colorizing is so much improved over days of yesteryear when colorizing was in it's primitive stages and not all items could be specifically colored. Before a face was just an orange blob, now a face includes white teeth, white eyes with either blue or brown and accurately colored hair. It's really fantastic. Right now, I have Season 2 of Bewitched colorized all on DVD. It's a joy to watch. I wish they'd colorized The Honeymooners, Superman, Lucy & Leave It To Beaver. It'd be great to see those shows in color!!

A few years ago, I came across Bewitched on the Hallmark Channel. I didn't know episodes had been colorized. After watching the episode for a while, a doubletake. Wait a minute, this is from the first season, it's been colorized! I thought at first it was one of the actual color episodes.
As you can see from my avatar, I'm all for it.

I've never seen the first season in color :-( Even though I would really like too ... I shall buy that for me for Christmas .. the Bewitched COLORIZED dvds =D