The mousewheel zoom is actually a feature of the mouse, and isn't built into IE. I can't comment on the other browsers.

If you have a "wheel mouse," and it works in IE, it should work in almost any program.

For those without a fancy mouse, if you really want to "zoom" on something on the net, with IE you can click on Print Preview, and in Print Preview ONLY, Alt+ and Alt- will zoom you in and out. When you've finished looking, just use Close instead of Print to go back to the "real" page. (Handy for reading the fine print in EULAs.)

John