Microsoft's Internet Explorer has always been a tricky thing to debug with. By itself IE's debug messages are less useful than a teapot made of chocolate due to it's inaccurate reporting of line numbers and generic error messages. However it is possible to debug in IE using other tools such as the Microsoft Script Debugger, though this one will not help us profile the code to see why it is running slow. For looking at what is loaded on a page (similar to the Net view of Firebug) you can use Microsoft Fiddler - HTTP Debugging Proxy. This isn't a tool that is on the Microsoft website, although it does appear to be one made by either Microsoft or an employee of Microsoft. So with this you can see if there are any files slowing your loading time down, but it won't profile the JavaScript. It seems at present the only way to profile in IE is to write JavaScript that monitors the start and end time of functions.
One ready made JavaScript library for profiling is FunMon. In their own words:
The JavaScript Function Monitor is a script-based debugging tool. It is very useful for identifying performance problems from within the browser. Works in Internet Explorer and Netscape Navigater 4.x and above, and in Mozilla-based browsers.
Unfortunately this is not as descriptive as Firebug, but it does give the execution times of functions that are run. This combined with Firebug Lite and console.log() would help performance fixing in IE a great deal.
