Shaking head.
In CSS one can control the mouse pointer (cursor) to a certain degree, but very limited and by no means cross browser compatible, meaning waste of your time to try it in my opinion:
http://www.echoecho.com/csscursors.htm
Adjusting CSS in iWeb is another issue altogether, i.e. the iWeb CSS toolkit is cool, but not sure if it supports this or custom styles. Like I said, even if it did, see disclaimer above.
-jim