Hi Alberto,
It's certainly possible to use the editor's extensibility model to change the look of comments in the code to make them stand out or convey additional information. For example, you could write a classifier to change the formatting (size, color, font, etc.) of any comment that begins with //TODO. The Text Coloring sample would be a good place to start for something like this. You could also write an adornment to change the visualization of comments, as shown in the blog post here. The VS 2010 Beta, coming very soon, will make extension development easier than it is in the CTP, so I'd encourage you to download it when it is released and give extensions a try!
Thanks for posting,
Brittany Behrens
Program Manager, VS Platform
http://blogs.msdn.com/vseditor