I have found a usable ASP.NET 2.0 sitemap editor from David Sussman with full source code, its offer basics feature which help you to boost up your site navigating building process, get it at http://www.ipona.com/samples/WebMenuEditor/Default.aspx
The WebMenuEditor is a Windows Forms 2.0 Application that provides a user interface for editing ASP.NET 2.0 Site Map files. The editor is pretty simple and supports loading and saving of SiteMap files, including custom attributes. A template site can be created from the SiteMap nodes, using VB or C#, code-inline or code-behind and standard pages or master/content pages.
Note that this is a work in progress and is a version 0.1 tool. It has been released now to allow people to use it before I get dragged into other project and have no further time to develop it. There are plenty of things that need doing to it, but it works well enough in its basic form. There's a small 'to do' list in the project