Yes, Install I.E.

http://psychocats.net/ubuntu/ies4linux

How do you install I.E on linux ?

It needs the shared files from Windows to run.

Or is there another I.E.

http://psychocats.net/ubuntu/ies4linux

Use WINE.........................................

why would you wanna use i.e. on ubuntu when there are so many more better web
browsers out there?

Because there are some sites that "require" you to use it. I dumped my
bank when they said I had to use IE. I said, 'close my accounts now
please.'

Why not use the "User agent Switcher" plugin ?
See : https://addons.mozilla.org/fr/firefox/addon/59

Just set your user agent to an IE signature. The server will think
you have an Internet explorer ... But it could cause problem with
some scripts and any activeX. So, test it with your problem site to
see if it works... It depends how they check the browser ID : with
some script or with the user agent string.

It depends upon the side doing the checking (as you said).
My wifes University is a stickler for IE. I tried everything I could and
couldnt get around it. Thats ok. She needs it for one class.

But the other thing about having IE on Ubuntu is testing site code
against IE and not a poser.

At work we use different Virtual Machines to run different OSs and
Browsers. If you have a fairly recent (big) machine, may be this
could be an avenue ?

Try installing Firefox with IE Tab, IE Tab emulates IE so you can use
IE only sites with Firefox

Does IETab works in Ununtu Firefox? I don't think so. Is it available?

I know the Konqueror browser allows one to tailor how ones system is identified
to remote devices.

Sorry I should have read twice your question. I had the impression
that it was the browser that was blocking you from accessing the web
site. Are you trying to launch the remote desktop via the MS web
interface ??? If yes, I think that this is simply a web interface
that call the MS Terminal Server thru an activeX of an ASP program.
Why not call yourself directly "rdesktop" the linux terminal server
client ? Once you are connected to your company network via modem,
the internet or a vpn you can reach a terminal server with rdesktop.

I have also tried, but Firefox addons/pluggins say IE Tab is not for
Linux OS yet.