The easiest way to switch the default application that handles the “View | Source” process in Internet Explorer is, in my opinion, using View Source Editor from Iconico Software.

The software is free. It’s amazingly simple. They don’t pay me a commission for plugging their product. No adware. No spyware. And have I mentioned already that it is simple and fast?

View Source Editor Download Link

However, if you crave pain and that “do it yourself” feeling, you can also use the Windows Registry to change IE’s default handling of displaying the source code for web pages.

The blog editor at My Digital Life has a nice explanation of the process posted. Here’s a preview of what they have to say: