Using IE on MAC

IE5.2.3 was the last version on the Mac and that was for the Power PC, not the current Intel machines.

you could install VMware or parallels and run IE in one of those programs.  

You can use the IE View Firefox plugin if you use Firefox. You need to customize a setting to make this work Mac OSX (instructions on such in the link below).

http://ieview.mozdev.org/

There used to be an version made available by MS but this has now been withdrawn. You could dual boot the Mac so that it runs a MS OS but that is a very expensive way to do it. I suspect that you need it for something that requires IE in order to give full functionality, such as OWA.
The latest versions of IE will not run but you can download up to version 8 using Winebottler.
There are some instructions here:
http://osxdaily.com/2010/04/20/run-internet-explorer-on-your-mac/

You can also run IE using Crossover, although it also depends on if you just want IE as a browser or as a launcher for some other web-based application. Anyway, check it out at www.codeweavers.com.

Why are you trying to use IE? If you are trying to use IE because you need to use an Activex control, as for instance to use Microsoft's Remote Web Workplace, you can forget it, because Activex has never and will never run on the Mac OS regardless of whether you are running IE.

If you want to run an Activex control, you have to run Windows on the Mac using Bootcamp, VMWare Fusion, or Parallels, or use an emulator like Crossovers.

If you tell us exactly what it is you need to do, we might be of more help.

Crossover works very well for me, I use it for certain website that need Internet Explorer to run.

It's not perfect, but the price point is very nice

I used to use Crossover to connect to our Remote Web Workplace at work and it worked quite well, but when we updated from SBS 2003 to SBS 2008, that broke it as Crossover did not support the newer version of RDC. Don't know if it has been updated to fix that in the meantime.

The problem with Crossover is that it supports a very limited range of applications and services.