While searching the Web I found a small and fantastic JavaScript Loupe that magnifies the portion of an image while you hover over it. This is the Loupe example (taken from the author's website)
Current version 1.3 supports all newer browsers: Firefox 1.5+, IE 6+, Opera 9+ and Safari. It can't be used on older browsers, but it won't be seen, so you don't have to worry about it. It is quite simple to use; just add onload="initLoupe(this.id);" to the image. It can do X-Ray magnifying as well.
It is free for private and non-commercial use. Visit Loupe website for more examples and information.
Really great piece of code!