Guidelines, a hidden feature for the Visual Studio Editor -- vstipEdit0015
So this is the first tip update I have done that has apparently been removed in VS2010. At the time of this writing I am talking with the VS editor folks to find out if the registry hack is, in fact, gone or just needs to go somewhere else. I will update this post if I discover any change.
With that said, if you are using Visual Studio 2010 there is an extension, created by Paul Harrington, you can use to have the guidelines:
http://visualstudiogallery.msdn.microsoft.com/en-us/0fbf2878-e678-4577-9fdb-9030389b338c
Read more: Visual Studio Tips and Tricks