If you are using visual studio.net 2003 and you are finding some html code or you want to see the html code for the particular source then document outline window will help you.
It provides the complete tree structure of a html code. So you can easily navigate through it and by selecting particular node will directly moves cursor to that control related code in html pane.
It is a very useful tool navigate between elements of a page or control.
You can see this windows by pressing Ctrl+Alt+ T or you can go through view->Other window -> Document Outline
Here is the screen shot for document outline window.