[calQlate]

ok.
First right click on the Lasso tool and choose the polygonal one, change the feather to about 5, you can toy with this setting until it looks good.

Now select the area you want to be colored, once selected right click inside of it and hit 'select inverse'. The polygonal tool is pretty simple to use, click where you want to start and move your mouse to the next location where you have to change direction or curve, click again and move your mouse from there, finish the selection by connecting back to the spot where you started.

Now go to Image -> Mode -> Grayscale

Hope this helped

Another method is to create show all mask layer..

1. First duplicate the original image.. Hit shift+D to duplicate the active image.

2. Now convert one to greyscale. Go to Image -> Greyscale

3. Select the greyscale image hit ctrl+c (this copys the greyscale to the clipboard)

4. Select the original color image and hit ctrl + L (this takes the greyscale copy from the clipboard and paste it on to the original as a new raster layer)

5. With your original selected locate your layers tool bar and you'll see you have a color layer and a greyscale layer.

6. Select the greyscale layer from the layers tool bar - then right click and hit create a new mask layer. (show all) (this creates another layer which is displayed as a white canvas)

7. Select this white canvas layer and then select a paint brush tool with solid black as the color.

8. Now just run your black paint brush over the areas to that you want to reveal color.
(Now worry if you mess up) Just grab a white paint brush to paint areas back to greyscale.

When working with masks remember. Black colors reveal the layers thats underneath -- and white covers using the highest promoted layer. (Which in your case would be the greyscale)