Given that IE hasn't run on anything other than Windows since version 5 (when it ran on Solaris, HP-UX, Xenix, and, I've heard Linux as well - up to 5.5 on Mac OS), I'd say they probably don't have any plans for it.
Though IE8 and possibly IE9 work in Wine, yes, that's not what I meant. I meant that Microsoft was actively developing and supporting native ports of IE 3 through 5 on Solaris, HP-UX, Xenix, and maybe possibly Linux (I couldn't find evidence, but I remember seeing something about it.)
For crying out loud, this comparison is apples to oranges, will people please stop making it? Microsoft have closed source operating systems and are leveraging that to stop competition. Mozilla is developing an open platform where anyone can modify it to run on a different browser.