Ok guys!
Here is my promised tutorial. In this tut, I'll explain how you can make a colored photo from a black and white photo.
I hope you guys can understand it and will enjoy to follow it. So, here it comes guys, good luck all

1. First of all, find a photo or picture you want to color.
I used this picture:

This is the author of the photo:
http://kiscso.deviantart.com/ 2. In this photo already is some color, so press Ctrl+Shift+U to desaturate the picture. Now all the colors are gone:

3.Ok, you've to think about the colors you're gonna use. And ofcourse the trees are gonna be green
So take one of the selectiontools, I use the polygonal selection tool. Because trees are difficult to select EXACTLY I would use feather 1 or 2.
Start with selecting the tree.(I used Feather:1) If you´re done with selecting... make a new layer, take the green color of your choice at forground color, and press Alt+Backspace to fill your selection with the green color.
>>>

TIP: How more time you spend on selecting everything...how better your result will be!
4. Ok, now you've filled your selection with the green of your choice. Now you only have to let it look real.
So click on your filled layer, and change the blendmode to Soft Light. It already looks real isn't it?
If you are happy with the result now, you don't have to do anything... You can deselect now.
But I wasn't really happy, so I changed the opacity to 80%
TIP: You can mess with all the settings, but if I were you, I would use Soft light the whole time, and I wouldn't make it TOO tranceparent.
5. Now repeat all the steps before, but on different objects. Like the house, and floor, the sky, etc...
You can change the opacity on every layer, and make much layers as possible, try to use 1 layer for every new color layer.
So 1 for the GREEN layer on the tree, one for the YELLOW layer for the basic color of the house, etc.
When I filled all the parts, without opacity changes or blendmode changes, my picture looked like this:

6. And about the sky, you have to use a hight feather.
I used feather 15, and then you have to select the sky and fill it with some blue. You can mess with some things and settings, but I guess it will look good most of the time.
I hope you guys enjoyed it, and this was my final result when I changed everything to Soft light and changed some opacity

Maybe this tutorial isnt really clear, but that's because I made it quite fast.
It isn't a full detail tutorial with everyting explained, but its more for the photoshop users, who know how to work with PS and can do all the things.
Its more to show how to do it, and not foloow everything I do
So if you have questions, or you see that I forgot something, tell or ask it

BTW, maybe add it to P2L to let them know this forum excists

?