I wrote some years ago HOWTO: Open the Web Browser and navigate to a page from a Visual Studio add-in or macro (http://www.mztools.com/articles/2008/MZ2008012.aspx). The other day someone asked in the MSDN VSX forum how to show an .aspx page in the browser programmatically, which is easy if you can get the full browse URL of the .aspx page. It happens that the ProjectItem class of Web Site projects and Web Application projects has different ways of getting / composing the browse URL, so I have written an article with sample code about this:

HOWTO: Get the full browse URL of an .aspx page
http://www.mztools.com/articles/2013/MZ2013002.aspx