Here's a tutorial geared towards beginners that explains removing or changing a background in Photoshop. While the tutorial was created using Photoshop CS2 this tutorial can be used in any version of photoshop (or in any editing program that has a lasso (selection tool), an eraser tool and the ability to work on layers) including Photoshop Elements.
There is more than one way to remove or change a background in Photoshop, and this method is the first in a series of three, so there will be two additional tutorials (later) that explain the other two methods I use.
This one is probably the most time consuming, but also is one that will be useful to widest range of people; the others will require the use of Photoshop and not everyone has photoshop, so this method was my first choice.
This method was also chosen because it teaches something besides isolating an object - it teaches you control using a mouse over tools such as the eraser and the lasso selector. It's a lot easier to use these tools (and the pen tool, which comes in a later tutorial) if you've got some practice.
It would be a lot easier to use a tablet and stylus for this, but not a lot of beginners have those tools at hand, so mouse control is part of what you'll learn in this.
Take an image from this:
You can download the tutorial from here: Removing or Changing a Background
And an image to isolate in the tutorial from here: Phone Original