The blur background is a photography 'trick', physics of light, aperture and lens. To blur the background, use a large aperture (small f-stop), but be careful, if you are using an SLR or digital SLR, too small an F-stop may give you a picture with Dept of field (the deprt that is in sharp focus) so shallow that only part of the subject is sharp.. let's say you shoot a dog and focus at the eyes... if you use too small an f-stop, you may end up with a picture where only the eyes are sharp whereas the nose and the rest are blurred. But if you are using consumer digital camera with lens that cannot be changed, this shouldn't be a problem... but the intensity of the of blur is limited, even if you use the smallest F-stop that is available. Other factors that affects the DOF is the distance between you and the subject and the subject to the background, as well as focal length of the lens.
To achieve black and white, use photoshop and desaturate the image by clicking image->adjust->desaturate or converting the picture to grey scale.
Images with parts in coulour is done with layers in photoshop... There are a few was to do it. One way will be creating a new layer on top of the image and copy the image onto the new layer, so that you have two layers that are exactly the same. Next, desaturate the top layer. Working on the desaturated top layer, Select the area you want in colour with the appropriate selection tools. When done, delete away the parts, the coloured layer below will show through. Now, you got an image with coloured and B&W elements.
This is just a brief explanation, if there's anything more, ask ask.
Hmmm to try to get a shallow DOF for a consumer camera, one way is to use the maximum optical zoom available, open up the aperture to the widest (smallest F-stop available) and position yourself so as that the subject is near to you while the background is very far away. Another way will be using the macro mode, but the DOF will become very very shallow. But otherwise it's very difficult.
Hmmmm... Hope I didn't scare away anyone.... sheesh... am I that scary?
a small f-stop means a wide aperture, just set the f-stop to a small number (try the smallest) under aperture piority mode to open up the aperture, the camera will automatically adjust the shutter to give the right exposure. If no aperture piority mode, only have manual mode, just set the aperture wide (small f-stop) and then adjust the shutter speed manually to achieve the right exposure. Use the LCD for this. Most LCD will show the effect of changing shutter speed and aperture. Another way will be get the aperture and shutter value using the auto mode, remember it. Go to manual, dial in those values, adjust the aperture, see how many stops you go up. Then adjust the aperture down the same number of stops you go up... er... confusing?
The F-stop or f-number is the aperture setting. When you half press the shutter, the camera should do a auto focus and display the exposure values, one is the shuter speed, commonly displayed as a fraction such as 1/250 and beside that you can see the f-stop, which is usually displayed like F3.5 or F(some number here). The F-stop is the aperture settings. So just refer to the manual on how to set this in manual mode...
Me having exams... I'll try to put in a more detailed example and instructions after the paper tomorrow.
Oh...I believe the pop up flash should be able to work as well, but have to take note of the power of the pop up flash, make sure it is powerful enough to illuminate the subject at the distance you are shooting, and there's nothing blocking the flash.... hee hee... such as your lens....
I'll try it out with my D5's built in flash when I have the time