Many ways to do this...just "Google it" or here are some general guidelines that work with most image editing software programs. 

-First, take the picture using a background color that is solid, not the same color as your product, is not shiny and without alot of wicked texture.  I have always had great luck with a light blue vellux blanket.
-Second, use the correct settings on your camera with the correct lighting!
-Third, bring your image into your image editing program, then use any of the following tools to rid the background, polygonal lasso, magic wand, magic eraser, or the eraser. The tool depends on the image.  Try them all.  It"s whatever works and whatever is easiest!  Clean it up the best you can zooming in to see what you are doing. Jagged, highly textured edges are the toughest.  I like to use the polygonal lasso and the zoom in real clost and soften and touch up the edges with your eraser.
-Fourth, add another layer below your image and fill it with white.

If you are having a really rough time...and prefer the easiest way...there is always the EZcube!  EZcube.com