Display tooltip for List Field Header in MOSS 2007

Display tooltip for List Field Header in MOSS 2007

Hi,
I have a requirement as below,
I need to show a tooltip for a list "field(column) header" and not list items level. Since, the field description can be seen only by users with edit permissions, i need to show the description of the field as tooltip for all read-only users of the list, when user hovers the mouse on list field header.

Could you please check and help me on the same?
Thank you.