In order to view a VNC server with IE, you need to specify the port its running on, but there are some additional things of which to make note.
First, IE is very finicky about the format of the URL you need to use. In order to view a host on the default port, the URL must be "http://host.domain:5800". Using just "host.domain:5800" will not work with IE (although it does work with Netscape and Mozilla).
Also, it's a good idea (and may even be necessary) to use Sun's Java runtime rather than Microsoft's own Virtual Machine.
After installing Sun's Java runtime, download the following utility to make it the default application handler for Java applets:
http://homepage1.nifty.com/emk/vmselect_e.html
In its readme, it also recommends disabling Microsoft's VM altogether, for security reasons. You can do this with the following command:
regsvr32 /u msjava.dll
Problems using Internet Explorer and VNC.
Moderator: jasonb