Can any one give me simple coding for zooming a image when mouse over.

condition is the zooming image may appear over my text field but it should not affect the alignment of the text field

You can do this with Magic Zoom. Or, you can use Magic Zoom Plus and the image will zoom on mouse hover and enlarge on mouse click:

http://www.magictoolbox.com/magiczoomplus/

We are the creators of this.