Adobe Photoshop CS2 Question

[cyclones]

I was looking through my friends' pictures and I saw one of them that I liked and I was wondering how you keep the color like that but still keeping the background a black and white color? Is there anyway to do that in Adobe Photostop CS2 cuz thats what I have??
THANKS!!

 

[peterhuang913]

keep the foreground and gray out the back?

 

[cyclones]

Can u show me step by step cuz i just downloaded photoshop and i have no clue how to do it?
Thanks

 

[Invisible]

i get all my help from here
Good-Tutorials / Photoshop Tutorials + Flash Tutorials