How do you make all but one color in a picture black and white?

Question:I've seen this a good number of times, and I like the effect. I've got photoshop 7.0, but I can't seem to figure it out.

You can find an example of what I'm talking about here:
http://tn3-1.deviantart.com/fs27/300W/i/...
and here:
http://img.photobucket.com/albums/v709/f...

So, who can help me out? I would like to know how to do this, or what other image editing programs I need to do it.

Best Answer - Chosen by Asker: I've seen this a good number of times, and I like the effect. I've got photoshop 7.0, but I can't seem to figure it out.

You can find an example of what I'm talking about here:
http://tn3-1.deviantart.com/fs27/300W/i/...
and here:
http://img.photobucket.com/albums/v709/f...

So, who can help me out? I would like to know how to do this, or what other image editing programs I need to do it.

You have a few choices:
You can go selectively color blind.
You can buy a selective colour camera (with a built in coffee-maker).

Or
you can simply desaturate then go over the area you want in colour with the history brush.. done.

Yeah, I'm feeling sarcastic tonight , the last one does work though.

There probably a few ways to do this. You can either use a personalized gradient, setting your own colours etc. Or simply desaturate (make it black & white) then use the airbrush, with a very soft spread. I cant remember the exact options for that now, sorry, I'll try get details for you at some point if you dont come right.